Bheritaas5 foundation

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VERITAS Storage Foundation
5.0 for UNIX: Maintenance
100-002353-8

COURSE DEVELOPERS
(;ail Adey
Bill4t.'Gerrits
TECHNICAL
CONTRIBUTORS AND
REVIEWERS
Jade Arrtngton
Marg) Cassid)
l{fI) Freeman
Jue (;allagher
Bruce(;arncr
Tomer (~urantz
Bill Havey
(;l'm,' Henriksen
(;l'rald Jackson
Ravmond Karns
Hill Lehman
IIflh Lucus
Dartvoue 'Ianikhong
Chrlstian Rabanus
naw I{flgers
Kleber Saldanha
Albrecht Seriha
,lieh.1 Simoni
Ananda Sil'iscnu
Pete TtH..-m mes
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Table of Contents
Course Introduction
VERITAS Volume Manager Maintenance Tasks
VERITAS Storage Foundation Curriculum .
Lesson 1: Maintaining Data Consistency
Resynchronization Operations .
Interpreting State Information for VxVM Objects
Modifying VxVM Object States ..
Lesson 2: Managing Devices Within the VxVM Architecture
Managing Components in the VxVM Architecture.
Discovering Disk Devices... . .
Managing Multiple Paths to Disk Devices .
Lesson 3: Encapsulation and Rootability
Placing the Boot Disk Under VxVM Control
Creating an Alternate Boot Disk ..
Removing the Boot Disk from VxVM Control.
Lesson 4: Troubleshooting the Boot Process
Operating System Boot Processes .
Troubleshooting the Boot Process .
Recovering the Boot Disk Group ..
Lesson 5: Volume Maintenance
Changing the Volume Layout..... .
Managing Volume Tasks... .
Analyzing Volume Configurations with Storage Expert .
Lesson 6: Performance Monitoring
Storage Performance Analysis Process ..
VxVM Performance Monitoring Tools and Techniques
Lesson 7: Point-ln-Tlme Copies
What Is a Point-In-Time Copy? ...
Types of PITC Solutions in Storage Foundation ..
Creating and Managing Volume Snapshots .
Using Volume Snapshots for Off-Host Processing
Creating and Managing Storage Checkpoints .
Lesson 8: Other Enterprise Features Overview
What Is Dynamic Storage Tiering? .
What Is Intelligent Storage Provisioning? .
What Is the Storage Foundation Management Server? .
tntro-z
. Intro-S
1·3
1·9
1·18
. .... 2·3
2·13
. 2·16
3·3
. 3·18
3·22
. 4·3
... 4-4
.... 4·15
5·3
5·12
5·21
6·3
6·7
7·3
. 7·8
7·17
7·27
7·31
. 8·3
. 8·10
8·18
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Table of Contents

Appendix A: Lab Exercises
Lab 1: Maintaining Data Consistency ...
Lab 2: Managing Devices Within the VxVM Architecture
Lab 3: Encapsulation and Rootability... .
Lab 4: Troubleshooting the Boot Process ..
Lab 5 Volume Maintenance. .
Lab 6: Performance Monitoring
Lab 7 Point-in-Time Copies.
Appendix B: Lab Solutions
Lab 1 Solutions: Maintaining Data Consistency ..
Lab 2 Solutions: Managing Devices Within the VxVM Architecture.
Lab 3 Solutions: Encapsulation and Rootability ....
Lab 4 Solutions: Troubleshooting the Boot Process
Lab 5 Solutions: Volume Maintenance ...
Lab 6 Solutions: Performance Monitoring .
Lab 7 Solutions Point-in- Time Copies ..
Appendix C: Boot Processes and VxVM Start-Up Scripts
VxVM and the Solaris Boot Process.
VxVM and the HP-UX Boot Process
Index
. A-3
· A-13
.... A-25
· A-35
. A-43
.... A-49
· A-63
. B-3
... B-21
. B-37
.. B-51
. B-65
. B-75
.. B-97
..... C-2
....... C-15
VERITAS Storage Founttetion 5.0 for UNIX: Maintenance

How does VxVM integrate into my system
architecture?
· How do I discover new devices?
· How do I manage dynamic multlpathing?
How can I recover critical data?
·How do I resolve disk failure?
· How do I recover a plex?
·How do I recover the boot disk?
How can I accelerate access to critical data?
·Where are the performance problems?
· How is my hardware affecting performance?
· How do I tune VxVM and optimize I/O?
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VxVM Maintenance
Device
Management
Recovery
Management
Performance
Management
VERITAS Volume Manager Maintenance Tasks
Before you perform any maintenance tasks, you should understand the VxVM
architecture and how to manage devices connected to your system.
When you encounter a problem on a system running VERITAS Volume Manager,
you must know how to accurately identify the problem and select the appropriate
solution. By learning how to use Vx VM recovery tools and apply recovery
techniques in appropriate ways, you can troubleshoot problems that may occur in
your environment and minimize the loss of critical data.
A variety or factors. such as hardware. location or data on drives. and the
application I!O profile. can impact the performance of VlRITAS Volume
Manager (VxVM). The pcrtonnancc management techniques discussed in this
training enable you to idcmily and remove performance bottlenecks without
disrupting users.and to accelerate accessto critical infornuuion.
tutro-Z
Copyrl~tll ~- 2006 Symantec Corpor auon fill nqtots reserved
VERITAS Storage Foundation 5.0 for UNIX' Maintenance

Storage Foundation Curriculum Path
VERITAS Storage
Foundation for
UNIX:
Fundamentals
••••••
VERITAS Storage
Foundation for
UNIX:
Maintenance
~------------ ------------~-----v--
VERITAS Storage Foundation for UNIX
symantec.
VERITAS Storage Foundation Curriculum
VERITAS Storag« Foundationfor UNIX: Maintenance training is designed to
provide you with comprehensive instruction on making the most of VERIT AS
Storage Foundation.
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Inlro-3Course Introduction

• Lesson 1: Maintaining Data Consistency
• Lesson 2: Managing Devices Within the
VxVM Architecture
• Lesson 3: Encapsulation and Rootability
• Lesson 4: Troubleshooting the Boot
Process
• Lesson 5: Volume Maintenance
• Lesson 6: Performance Monitoring
• Lesson 7: Point-in-Time Copies
• Lesson 8: Other Enterprise Features
Overview
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VERITAS Storage Foundation for UNIX: Maintenance Overview
This training provides instruction on device management, troubleshooting,
recovery, and performance monitoring lorusers ofVERITAS Storage Foundation.
Objectives
After completing this course. you will be able tu:
Interpret plcx. volume, and kernel states, fix plcx and volume failures by using
VxVM tools. and resolve data consistency problems by analyzing plex states.
Describe the Vx VM architecture and manage the device discovery layer and
dynamic multipathing feature.
Place the rout disk under Vx Vlvl control and mirror the root disk.
Identify boot processes. debug VxVM during system start-up, and resolve boot
disk problems.
Rccoufigurc volumes online and use the Storage Expert utility to analyze
volume configurations,
Monitor VxVM performance and identify how volume configuratious
contribute tu performance optimization.
Create and manage Instant volume snapshots and storage checkpoints,
Describe Dynamic Storage Tiering (DST). Intelligent Storage Provisioning
(ISP). and the Storage Foundation Management Server (SFMS).
Intro-4
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VERITAS Storage Fountietiot) 5.0 for UNIX: Meintenence

Course Resources
• Lab Exercises (Appendix A)
• Lab Solutions (Appendix B)
• Boot Processes and VxVM Start-Up Scripts
(Appendix C)
Additional Course Resources
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Appendix A: Lab Exercises
This section contains hands-on exercises that enable you to practice the concepts
and procedures presented in the lessons.
Appendix B: Lab Solutions
This section contains detailed solutions to the lab exercises for each lesson.
Appendix C: Boot Processes and VxVM Start-Up Scripts
This section contains a summary of the scripts involved in VxVM startup.
Course Introduction
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Intro-5

Typographic Conventions Used in This Course
The following tables describe the typographic conventions used in this course.
Typographic Conventions in Text and Commands
Cuuveution
Courier New.
bold
Element
Command input.
both syntax and
examples
Examples
To display the robot and drive configuration:
tpconfig -d
1"0 display disk information:
vxdisk -0 alldgs list
Courier New.
plain
Courier New,
Italic. bold or
plain
Command output
Command
names. directory
names. tile
names. path
name'S. user
names.
passwords. L RLs
when used within
1"1'glll'll'tcxt
paragraphs,
Varia hies in
command syntax.
and examples:
Variables in
command input
arc Italic. plain.
Variable, in
command (Hit put
arc Italic. bold.
In the output:
protocol minimum: 40
protocol_maximum: 60
protocol current: 0
Locate the al tnames directory.
Cio to http://www.symantec.com.
l.nrer the value 300.
Log011 asuser 1.
To install the media server:
/ cdrom_ directory/ install
To ~I•.cessa manual page:
man command name
To display detailed information tor a disk:
vxdisk -g disk_group list
disk name
Convention
Typographic Conventions in Graphicailiser Interface Descrlptlons
Arrow
Element Examples
~--------------~
Menu navigarion paths Select l-ile- ->Save,
Initial capitalization Hunons. menus. window». Select tire Next button.
options. and other interface Open the Task Status
clements window.
Remove the checkmark
from the Print File check
box.
Quotation marks Interface clements with
long names
Select the "Include
subvolumes in object view
window' check box.
lntro-B VERITAS Storage Foundation 5.0 for UNIX: Maintenance
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Lesson 1
Maintaining Data Consistency

Lesson Introduction
• Lesson 1; Maintaining Data •••
.. _Q~n~s~st~'!.£l'______.~ --i
• Lesson 2: Managing Devices Within
the VxVM Architecture
• Lesson 3: Encapsulation and
Rootability
Process
Overview
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Lesson Topics and Objectives
Topic After completing this lesson, you
will be able to:
--
Topic 1: Resynchronization Describe mirror resynchronization
Operations processes.
Topic 2: Interpreting State Interpret plex state and condition
Information for VxVM flags, volume states, and kernel
Objects states.
Topic 3: Modifying VxVM Fix plex and volume failures by using
Object States VxVM tools.
1-2 VERITAS Storage Foundation 5.0 for UNIX. Maintenance

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IResynchronization is the process of ensuring that after a
system crash:
• All mirrors in a volume contain exactly the same data.
• Data and parity in RAID-5 volumes agree.
Ig~~~:::==~1Did all writes
'; complete?
Do all mirrors
contain the
same data?
Types of mirror resynchronization:
• Atomic-copy resynchronization
• Read-writeback resynchronization
Resynchronization Operations
What Is Resynchronization?
Resynchronization is the process of ensuring that. after a system crash:
All mirrors in mirrored volumes contain exactly the same data.
Data and parity in RAID-5 volumes agree.
Data is written to the mirrors of a volume in parallel. If a system crash occurs
before all the individual writes complete. some writes may complete while other
writes do not. This system crash can cause 111'0 reads from the same region of the
volume to return different results ifdifferent mirrors are used to satisfy the read
request. In the case of RA ID-5 volumes. two reads returning different results can
lead to rarity corruption and incorrect data rcconstrucuon. VxVM uses volume
resynchronization processes to ensure that all copies of the data match exactly.
VxVM records when a volume is first written to and marks it as dirty. When a
volume is closed by all processes or stopped cleanly by the administrator. all
writes have been completed. and Volume Manager removes the dirty flag for the
volume. Only volumes that are marked dirty when the system reboots require
resynchronization.
Not all volumes require resynchronizarion after a system failure. Volumes that
were never written or that had no active 1/0 when the system failure occurred do
not require resynchronization.
The volume is completely accessible during the two modes of resynchronizaiion.
Lesson 1 Maintaining Data Consistency 1-3
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Atomic-Copy Resynchronization
Atomic-copy rcsynchronizauon refers to the sequential writing of ~II blocks of the
volume to a plcx. This operation is used anytime a new mirror is added to a
volume, or all existing mirror is in stale mode and has to be rcsynchronizcd.
Atomic-Copy Resynchronization
Atomic-copy resynchronization involves the
sequential writing of all blocks of a volume to a plex.
This type of resynchronization is used in:
• Adding a new plex (mirror)
• Reattaching a detached plex (mirror) to a volume
• Online reconfiguration operations:
- Moving a plex
- Copying a plex
- Creating a snapshot
- Moving a subdisk
Atomic-Copy Resvnchrunizatlon Process
1 The plcx being copied to is set tu a write-only state.
2 A read thread is started on the whole volume. (Every block is read intcrnally.)
3 Blocks arc written from the "good' plcx tu the stale or new plcx.
1-4
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Read-Writeback Resynchronization
Read-writeback resynchronization makes all plexes
identical by alternately copying regions between
plexes.
This type of resynchronization is used in:
• Recovery of mirrors after a system crash
• Growing a volume
In this type of resynchronization:
• Mirrors marked ACTIVE remain ACTIVE, and the
volume is placed in the SYNC state.
• An internal read thread is started. Blocks are read
from the plex specified in the read policy, and the
data is written to the other plexes.
• Upon completion, the SYNC flag is turned off.
Read-Writeback Resynchronization
Read-writeback rcsynchronization is a process of ensuring that two plcxes have
the same content.
Because the application must ensure that all writes arc completed. the application
must fix any writes that are not completed. The responsibility ofYxYM is to
guarantee that the mirrors have the same data.
A database (as an application) usually docs this by writing the original data
back to the disk.
A tile system checks to ensure that all of its structures are intact. The
applications using the tile system must do their own checking.
Read-Writeback Resynchronlzatlon Process
All plexes that were ACTIVE at the time of the crash are set to the ACTIVE
state again. and the volume is placed in the SYNC state (or the NEEDSYNC state
if the disk group has more than one volume).
2 An internal read thread is started to read the entire volume. and blocks are read
from whatever plex is in the read policy and are written hack to the other
plexcs, Because the default read policy is Select and this chooses Round Robin
over Preferred. blocks are read from one plcx and written to another.
alternately.
3 When the resynchronization process is complete. the SYNC flag is turned off
(set to ACTIVE).
User-initiated reads are also written to the other plexcs in the volume but otherwise
have 110 effect 011 the internal read thread.
Lesson 1 Maintaining Data Consistency
Copyright if 2006 Sy!l181l1eC Corporanon. /III "gtll~ reserv-e
1-5

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Impact of Resynchronization
Resynchronization takes time and impacts
performance.
To minimize this performance impact, VxVM provides
the following solutions:
• Dirty region logging for mirrored volumes
• RAID-5 logging for RAID-5 volumes
• FastResync for mirrored and snapshot volumes
Minimizing the Impact of Resynchronization
The process of rcsynchronizauon call impact system performance and can take
time. Tu minimize the performance impact otrcsynchronizmion. VxVM provides:
Dirty region lugging lor mirrored volumes
RAID-5 logging lor RAID-5 volumes
FastResync lor mirrored and snapshut volumes
Till; FastResync option requires the lluslrSnup license.
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Dirty Region Logging
• For mirrored volumes with logging enabled, DRL
speeds plex resynchronization. Only regions that
are dirty need to be resynchronized after a crash.
• If you resize a volume, the log size does not change.
To resize the log, you must delete the log and add it
back after resizing the volume.
Dirty Region Logging
You were introduced to dirty region logging (DRL) when you created a volume
with a log. This section describes how dirty region logging works.
How Does DRL Work?
DRL logically divides a volume into a set of consecutive regions and keeps track
of the regions to which writes occur. A log is maintained that contains a status bit
representing each region of the volume. For any write operation to the volume. the
regions being written are marked dirty in the log before the data is written.
If a write causesa log region to become dirty when it was previously clean. the log
is synchronously written to disk before the write operation can occur. On system
restart, VxVM recovers only those regions of the volume that are marked as dirty
in the dirty region log.
Log subdisks store the dirty region log of a volume that has DRL enabled.
Only one log subdisk can exist per plex.
Multiple log subdisks can be used to mirror the dirty region log.
If a plcx contains a log subdisk and no data subdisks. it is called a log pier.
Only a limited number of bits can be marked dirty in the log at any time. The dirty
bit for a region is not cleared immediately after writing the data to the region.
Instead. it remains marked asdirty until the corresponding volume region becomes
the least recently used.
1-7Lesson 1 Maintaining Data Consistency
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ji·}_I·
Dirty Region Logging: Example
0123 ...
[0010000.-::-0 0 100 .. 000 ... 0 0~iiJ
01 23 ...
[O!OOOOO... 00000 .. 000 ... O~
Active
Bitmap
Volume
DRL Before a Crash
J=;;:;::::I 0
1
2
3
Recovery
Bitrnap
II
DRL After a Crash
~ 0123 ...
): : LL_~_~_:_1_~_:_':_:_,,_. _:_:_:_0_0_:_·._:·._:_:_:_·.·.·_.:_O_~_:_:_:_:_I_R_~_~~_~_~_;y---J
Dirty Region Log Size
In the dirty region log:
A small number of bytes of the DRL arc reserved for internal use. The
remaining bytes arc used forthe DRL biunap,
The bytes arc divided into two bitmaps: an active biunap and a recovery
biunap.
Each bit in the active biunap maps to a single region of the volume.
A maximum of 204S dirty regions per system is allowed by default.
How the Bitmaps Are Used in Dirty Region Logging
Both bitmaps arc zeroed when the volume is started initially, after a clean
shutdown. As regions transition to dirty, the corresponding bits arc set before the
wntcs to the volume occur.
If the system crashes, the activ c map is OR' d with the recovery map.
Mirror rcsyuchronizatiun is now limited to the dirty bits in the recovery map.
The active map is simultaneously reset, and normal volume ''0 is permitted.
Usageof two biunaps in this way allows VxVM to handle multiple system crashes.
Copyright 2006 Svmaotec Corporanon All flgills reserved

symantcc
Why Is It Important to Understand Object States
• VxVM uses plex and volume states or condition flags to decide:
- If a volume can be started
- If a mirrored volume needs any synchronization
- Which copy of data (plex) is to be used as the source if
synchronization is required
- If I/O is allowed to different copies of data (plexes)
• You may need to manipulate plex or volume states under certain
conditions:
- To recover volumes if one or more failures prevent VxVM from
taking automatic recovery actions
- To recover from situations where interrupted configuration
tasks leave volumes in unusable states
- To take specific copies of data out of the I/O path for
maintenance purposes
- Use disk group configuration backups to create specific
configurations
Interpreting State Information for VxVM Objects
VxVM uses plcx and volume states or condition Ilags to decide which operations
can be performed.
You may need to manipulate plex or volume states under certain conditions.
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syrnanter
How Volumes Are Created
vxassist is a top-down utility-that is, you only
specify the properties of the volume you want to
create-that creates volumes bottom-up:
1. Create subdisks.
2. Associate subdisks to plexes.
3. Associate plexes to a volume.
4. Initialize the volume's plexes.
5. Start the volume.
How Volumes Are Created
In order to troubleshoot and solve problems associated with mirrors, you must
understand how volumes arc created. The vxassi st utility is a top-down utility.
which means that you specify only the properties of the volume that you want to
create. However, vxassist actually creates the volumes using a bottom-up
approach. which means that subdisks an: created first and used to build volumes.
To create a volume, vxassi st follows this process:
Determine where you 1 ill place the data and create subdisks on the appropriate
disk drives.
2 Create mirrors and associate each of the subdisks to the mirrors that will be
used in the volume.
3 Create the volume and associate the mirrors to the volume. The result is a
volume with one or more plcxcs.
4 Initialize the volume's plcxcs by selecting the plcx that represents the data for
the volume. You perform this action by using the vxvol ini t command.
Initializing a volume is similar to using a low-lcvcl lormat command on a disk
drive: it states how to nuvig.uc to the data. (13ydefault. vxassist creates
both plcxcs as hay ing the data and copies them together-using rcad-writcback
synchronization. )
5 Start the volume. Starting a volume involves enabling the area that the volume
represents on disk, and enabling its object in the disk group configuration
database. to accept user and system 1,'0.
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Identifying Plex Problems
To identify and solve pie x problems, use the
following information:
• Plex states
• Volume states
• Plex kernel states
• Volume kernel states
• Object condition flags
Commands to display plex, volume, and kernel states:
vxprint -g diskgroup -ht [volume_name]
vxinfo -p -g diskgroup [volume]
You can use STATE fields in the output of the vxprint and vxinfo commands
to determine that a problem has occurred, and to assist in determining how to fix
the problem, VxVM displays state information for:
Plcx states
Volume states
Plcx kernel states
Volume kernel states
Identifying Plex Problems
The plex and volume state fields are not always accurate, because administrators
can change them. However. kernel state flags are absolute; that is, only VxVM can
change them. Therefore, kernel state flags arc always accurate.
A particular plex state docs not necessarily mean that the data is good or bad. The
plex state represents VxVM's perception of the data in a plex. VxVM is usually
conservative; that is, ifVxVM detects that data is not synchronized. then the plcx
states are set accordingly.
Lesson 1 MaintainingData Consistency
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1-11

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Displaying Object States
vo I volOl
plex voIDl-Q!
plex volOl-02
Esgen
ACTIn
ACTIVE
Sta.rted
vxinfo -p -g datadg volOl
vxprint -g datadg -ht volOl
v NAME PVG!VSET/CO KSTATE STATE LENGTH READPOL PREFPLEX
UTYPE
PL NAME VOLUME KSTATE STATE LENGTH LAYOUT NeQL/WID MODE
so NAME PLEX DISK DISKOFFS LENGTH [COLI) OFF DEVICE MODE
sv NAME PLEX VOLNAME NVOLLA YR LENGTH tcor./: aFF !>.MINH MODE
v voiOl ENABLED ACTIW 204800 SELECT fsgen
pi 10101-01 volO! ENABLED ACTIV!: 205200 CONCAT RW
ad datadgOl 01 voIOl-O! datadgOl 0 205200 0 diskO 1 ENA
p I volOl-02 voiOl ENABLED ACTIVE 205200 CONCAT RW
sd datadg02-01 volOl-02 datadg02 0 205200 0 diskO 2 ENA
Example of vxinfo and vxprint
If you do not specify the volume name on the command line for the vxprint or
vxinfo commands, information on all the volume, within the specified disk
group is displayed.

syruantec
Plex States and Condition Flags
EMPTY
• CLEAN (SNAPDONE)
ACTIVE (SNAPDONE) Pl:ENABLED/ACTIVE
P2:ENABLED/ACTIVE
[V: ENABLED/ACTIVE]
I vxvol start ~J Eval stopvi
Key
~
Pl:DISABLED/CLEAN
P2:DISABLED/CLEAN
[V: DISABLED/CLEAN]
i
P1: 1st Plex States j
P2: 2nd Plex States 1
[v: Volume States} i
Interpreting Plex States
Plex States
EMPTY: When you creme a volume, all of the plexes and the volume are set to the
EMPTY state.This state indicates that you have not yet defined which plex has the
good data (CLEAN). and which plcx does not have the good data (STALE). You can
only achieve the EMPTY state by creating a new volume using vxmake. or by
using related administrative commands.
CLEAN: The CLEAN state is normal and indicates that the plex has a copy of the
data that represents the volume. CLEAN also means that the volume is not started
and is not currently able to handle 110 (by the administrator's control).
ACTIVE: The ACTIVE state is the same as CLEAN. but the volume is or was
currently started, and the volume is or was able to perform 110.
SNAPDONE: The SNAPDONE state is the same as ACTIVE or CLEAN, but
SNAPDONE is a plcx that has been synchronized with the volume as a result of a
vxassist snapstart operation. After a reboot or a manual start of the
volume. a plcx in the SNAPDONE state still exists. It is persistent.
1-13Lesson 1 MaintainingDataConsistency
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Plex States and Condition Flags
STALE (SNAPATT)
OFFLINE
TEMP
Key
~
P1: tst Plex States
P2: 2nd Plex States
[V: Volume States)
STALE: The STALE state indicates that VxVM detects that the data in the plcx is
not synchronized with the data in the CLEAN plcxcs. This state is usually causedby
taking the plcx offline (110 can still be going to the other plcxcs, making them
unvynchronizcd) or by a disk tailurc-c-which means that the plcx was not updated
when new writes came into the volume.
SNAPATT: The SNAPATT state indicates that the object is a snapshot that is
currently being synchronized but docs not yet have a complete copy of tile data.
OFFLINE: The OFFLINE stare indicates that the administrator has issued the
vxmend of f command on the plcx. The plcx does not participate in any I/O when
it is offline, so actively writing to the volume causesthe contents to become
outdated. When the administrator brings the plcx back online using the vxmend
on command, the plcx changes to the STALE state.
TEMP: The TEMP state flags (TEMP, TEMPRM, TEMPRMSD) usually indicate that the
data was never a copy olthc volume's data, and it is recommended that you not use
these plcxcs. These temporary states indicate that the plcx is currently involved in
a synchronization operation with the volume,
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Note: If the volume is nonredundant at the time that
you reattach the drive, the plex state changes from
NODEVICE to FE COVER instead of IOFAIL.
Condition Flags
If a plcx is not synchronized with the volume and VxVM has information about
why it is not synchronized. then a condition flag is displayed. Multiple condition
flags can be set on the same plex at the same time. Only the most informative flags
are displayed in the state field of the vxprint output. For example, if a disk fails
during an I/O operation, the NODEVICE, IOFAIL, and RECOVER flags arc all set
for the plex, but only the NODEVICE flag is displayed in the state field.
NODEVICE: NODEVICE indicates that the disk drive below the plcx has failed.
REMOVED: REMOVED has the same meaning as NODEVICE. but the system
administrator has requested that the device appear to have failed (for example. by
using the vxdiskadm option. "Remove a disk for replacement").
IOFAIL: IOFAIL is similar to NODEVICE, but it indicates that an unrecoverable
failure occurred on the device, and VxVM has not yet verified whether the disk is
actually bad. (110 to both the public and the private regions must fail to change the
state from IOFAIL to NODEVICE.)
RECOVER: The RECOVER flag is set on a plcx when two conditions arc met:
A failed disk has been fixed (by using vxreattach or the vxdiskadm
option, "Replace a failed or removed disk").
The plex was in the ACTIVE state prior to the failure,
This flag indicates that even after fixing the volume, additional action tlIay be
required. The data may be lost and must be recovered from backup, or the
administrator must verify that the data on the disk is current by using utilities
provided by the application that uses that volume.
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Volume States
• EMPTY } These volume states have the same
• CLEAN meanings as they do for plexes.
ACTIVE
• NEED SYNC This state is the same as SYNC, but
the internal read thread has not
been started.
• SYNC Plexes are involved in read-
writeback or RAIO-5 parity
synchronization.
• NODEVICE None of the plexes have currently
accessible disk devices
underneath the volume.
Interpreting Volume States
Volume States
EMPTY, CLEAN. and ACTIVE: The EMPTY. CLEAN. and ACTIVE volume states
have the same meanings as they do for plcxcs.
NEEDSYNC: The NEEDSYNC volume state is the same as SYNC, but the internal
read thread has not been started. This state exists so that volumes that use the same
disk arc not synchronized at the same time, and head thrashing is avoided.
SYNC: The SYNC volume state indicates that the plcxcs arc involved in read-
writcback or RAID-S parity synchronization:
Each time that a read occurs from a plcx, it is written back to all the other
plcxcs that arc in the ACTIVE state.
An internal read thread is started to read the entire volume (or, alter a system
crash. only the dirty regions ifdirty region logging (DIU.) is being used).
forcing the data to be synchronized completely. On a RAID-S volume, the
presence ofa RAID-S log decreases the time ofa SYNC operation.
Starting an empty mirrored volume by using the vxvol start command places
the volume in SYNC mode.
NODEVICE: The NODEVICE volume state indicates that none of the plcxcs have
currently accessible disk devices underneath the volume.
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Kernel States
Kernel states represent VxVM's ability to transfer 110
to the volume or plex.
• ENABLED The object can transfer both system
110and user 110.
The object can transfer system 110,
but not user 110(maintenance mode).
No 110can be transferred.
Kernel states represent VxVM ability to transfer 1/0 to the object.
Volume kernel stat 1': VxVM's ability to transfer I/O to the volume
Plex kernel state: VxVM's ability to transfer I/O to the plex
ENABLED: The ENABLED kernel state indicates that the object is currently able to
transfer system I/O to the private region and user I/O to the public region.
DETACHED: The DETACHEDkernel state indicates that the object can currently
transfer system I/O. but 110t user [/0. This state is also considered the maintenance
mode where internal plex operations and ioct 1 functions arc accepted.
DISABLED: The DISABLED state is the offline state for the volume or the plex.
When all object is in this state. no I/O is transferred.
• DETACHED
• DISABLED
Interpreting Kernel States
Kernel States
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Example Scenarios
• SCENARIO 1:
- You are planning to go through an upgrade procedure that may
corrupt data. You want to keep one safe copy in case things go
wrong.
- You do not have enough space to add snapshot volumes, so
you take one plex out of the 110 path during the upgrade .
• SCENARIO 2:
- You are mirroring a critical application data across disk arrays
in multiple sites.
- A disaster first causes your remote site to be temporarily
disconnected and then causes the primary copy to be lost
permanently before you can recover from the temporary
failure.
- You now have the option of using the remote site data, which
is several minutes old, or recovering from last night's backup.
Modifying VxVM Object States
Example Scenarios
Determine the best action 1'01' the: scenarios that arc described on the slide.
1-18
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Solving Plex Problems
Commands used to fix plex problems include:
• vxrecover
• vxvol -f start
• vxmend fix
• vxmend off Ion
Resolving Plex Problems
When resolving disk and plcx problems, after you fix the underlying disk drives by
using the disk commands, you must fix plcx problems by using the following
commands:
• vxrecover
• vxvol -f start
• vxmend fix
• vxmend off Ion
Copvnuht (' 2006 Syraantec Corporation. All nqhts reserved

When vxrecover is executed. VxVM notes the state of the plcxcs in the volume.
lfboth ACTIVE and STALE plcxcs exist. the ACTIVE plcxcs issue unconditional
block writes over the STALE plcxcs, If there arc only ACTIVE plcxcs. the
rcad-wriicback copy procedure is performed.
Recovery is performed only on volumes that require recovery (such as volumes
marked as dirty before a sudden system failure). During the recovery process. the
volume remains online and started. When the synchronization process is complete,
the volume and all of its plcxcs arc ACTIVE and ENABLED.
Running vxrecover without specifying a volume name can cause a
synchronizauon operation to be started in parallel on all volumes that need
recovery. One synchronization operation runs on each drive (if necessary), and
volumes on different drives are synchronized in parallel.
Synchronization can affect system performance. If you have many volumes that
need to be recovered. you may prefer to:
Start the volumes without recovery by using vxrecover - sri.
Note: The - s option is only used when the volume is stopped.
2 Recover individual volumes or recover all of the volumes when I/O traffic is
lo« by u,ing vxr e cove r.
Note: As lung as one CLEAN or ACTIVE. non-volatile plcx (a plcx with no Ilags
set) is available inside a volume. you can start the volume using that plcx. The
administrator can recover any other plcxcs in the volume immediately. or defer
recovery to a later time.
Recovering Volumes
vxrecover -g diskgroup -8 [volume]
• Recovers and resynchronizes all plexes in a started
volume
• Runs the vxvol start and vxplexatt
commands (and sometimes vxvol resync)
• Works in normal situations
• Resynchronizes all volumes that need recovery if a
volume name is not included
• Examples:
vxrecover -s
vxrecover -s vol0l
The vxrecover Command
1-20
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vxvol -g diskgroup -f start volume name
• This command ignores problems with the volume
and starts the volume.
• Only use this command on nonredundant volumes.
If this command is used on redundant volumes,
data can be corrupted unless all mirrors have the
same data.
• Example:
vxvol -g datadg -f start volOl
vxvol -f start volume name
When you force a volume to start:
Ifall plexes have the same state. then read-writcback synchronization is
performed.
If the pie xes do not have the same state. then atomic-copy rcsynchronization is
performed.
The vxvol start Command
If a volume does not start with this command. it usually indicates that there is a
problem with the underlying plcxes.
Forcing a Volume to Start
If you add the - f flag. YxYM ignores the underlying problem and forces the
volume to start:
Caution: Force-starting a volume can have catastrophic resuits. Use extreme
caution when force-starting a mirrored volume after a disk failure and
replacement. Forcing a mirrored volume to start can unconditionally synchronize
the volume using a rcad-writeback method of alternating between plex blocks.
NULL plex blocks may overwrite good data in the volume. corrupting the data.
Only perform a forced start 011 a nonredundant volume.
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1-21

Modifying Plex and Volume States Manually
syrnaniec
• The volume that the plex is associated with must be in DISABLED
mode to modify the plex state.
• You may need to move a plex to STALE state as an intermediate
step before changing to CLEAN or ACTIVE state.
• Use this command as a last resort if none of the other recovery
options help.
vxmend -g diskgroup fix option object
• stale
• clean
• active
• empty
(only used on a volume)
Examples:
vxmend -g datadg fix stale volOl-Ol
vxmend -g datadg fix clean volOl-Ol
The vxmend Command
To manually reset or change the stare ofa plcx or volume, you can use the vxme nd
fix command.
Use this command if you know more about a plcxs data than YxYM docs. You
can only set plcx states with vxrne nd fix when the host volume or the plcx is
stopped.
Caution: Use caution and discretion when issuing the vxmend fix command
and its options. The vxmend fix command changes states set and cleared
automatically by the vxconfigd daemon. Ifused incorrectly. this command can
make the plcx, its volume, and its data inaccessible, and you may have to restore
the data Irom backup.
1-22
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vxmend -g diskgrollp on plex_name
Taking Plexes Out of the 1/0 Path
When analyzing plexes, you can temporarily take
plexes offline while validating the data in another plex.
• To take a plex offline, use the command:
vxmend -g diskgrollp off plex_name
• To take the plex out of the offline state, use:
vXIIlend off Ion
When analyzing plex problems to determine which plex has the correct data. you
may need to take some plcxes offline temporarily while you are testing a particular
plex by using this command.
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Example: If the Good Plex Is Not Known
The volume is disabled and not startable, and you do not
know what happened. There are no CLEAN plexes.
To resolve:
1. Take all but one plex offline
and set that plex to CLEAN.
2. Run vxrecover -so
3. Verify data on the volume.
4. Run vxvol stop.
5. Repeat for each plex until
you identify the plex with
the good data.
P1 RvolOl-Ol: volOl-02:
DISABLED/STALE :DISABLED/STALE
Analyzing Plex Problems
Example: If the Good l'Icx Is :'IIot Known
What if both plcxcs are in the STALE state? Regardless of what happened to the
plcxcs or the disks underneath. it is not sale to guess which plcx has the more
recent (or good) data and start the volume.
I I' you arc not sure which plcx has good data, then the salest solution is to test each
plcx one by one.
1 Take all but one plcx online and set that plcx to CLEAN.
2 Run vxrecover - s.
3 Verify data on the volume. Mount the file system as read-only so you do not
have to run a file system check.
4 Run vxvol stop.
S Repeat for each plcx until you identity the plcx with the good data.
This process requires step-by-step attention 10 all volume and plcx object details.
Use vxprint -ht to monitor any volume and plcx state changes that occur as a
result of your vxmend commands.
Without a method to test the validity of the datu, you must restore the data from
backup. For example. if your application is staning. call you guarantee that the
data it contains is the 1110strecent With a Iilc system. is f sck enough to guarantee
that the data in a file is there'! Even if you can mount the file system. you can lose
the data in some files in the process.
1-24 VERITAS Storage Foundation 5.0 for UNIX Maintenance
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If the Good Plex Is Not Known: Example
In the example, you can resolve the problem by using the following commands.
Set the good plex to CLEAN.
vxmend -g diskgroup off volOl-02
vxmend -g diskgroup fix clean volOI-OI
Verity that data is on the plcx by using the volume:
vxrecover -s volDI
vxvol -g diskgroupstop volOI
vxmend -g diskgroup -0 force off voIOI-Ol(lastcleanplexin
the volume)
vxmend -g diskgroupon volOl-02
vxmend -g diskgroupfix clean volOl-02
Verity that data is on the plcx by using the volume:
vxrecover -s volOI
If the current plex (vol01-02) has the correct data:
vxmend -g diskgroupon volOl-Ol
vxrecover volOI
If vol 01- 01 had the correct data:
vxvol -g diskgroup stop volOl
vxmend -g diskgroup fix stale volOl-02
vxmend -g diskgroup on volOl-Ol
vxmend -g diskgroup fix clean volOI-OI
vxrecover -s volDI
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symanrec.
Appendix l3 provides complete lab instructions and solutions. "1 ab 1S"luiiull''':
lJiIIL}ljJl[l~ !)~!u{ I)li,j'li,.'n<..'l P~!~'..'H··~
Lesson Summary
• Key Points
This lesson described mirror resynchronization
processes. This lesson also introduced the various
states in which Volume Manager objects. such as
volumes and plexes. can exist and described the
tools that you can use to solve problems related to
data consistency by analyzing and changing these
states.
• Reference Materials
- VERITAS Volume Manager Administrator's Guide
- VERITAS Volume Manager Troubleshooting Guide
Lab 1
Lab 1: Maintaining Data Consistency
In this lab, you practice recovering from a
variety of plex problem scenarios, and
optionally, observe the benefits of a dirty
region log during a system crash.
To investigate and practice recovery
techniques, you will use a set of interactive
lab scripts.
For Lab Exercises, see Appendix A.
For Lab Solutions, see Appendix B.
Labs and solutions for this lesson JI'C located on the:Iollo« ing pages:
Appendix A provides complete lab instructions. "1 dh i Llililciiillnc:: ):i1:1
{·on"i'kHt.·~,'· pa~i,l'/"'~
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Lesson 2
Managing Devices Within the VxVM
Architecture

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Lesson Introduction
Lesson 1: Maintaining Data
Consistency
• ~:~Y;Y~;~~r&;!~~~~ices ~ithin ..-
Lesson 3: Encapsulation and
Rootability
Lesson 4: Troubleshooting the Boot
Process
Lesson 5: Volume Maintenance
Lesson 6: Performance Monitoring
Lesson 7: Point-in-Time Copies
Lesson 8: Other Enterprise Features
Overview
svrnantec
Topic After completing this lesson. you will be
able to:
Topic 1: Managing
Components in the VxVM
Architecture
Manage components of the VxVM architecture,
including the VxVM configuration database,
the configuration daemon, and volboot.
Topic 2: Discovering Disk
Devices
Describe the VxVM device discovery function.
Topic 3: Managing Multiple
Paths to Disk Devices
• Describe how dynamic multipathing works
with active/active and active/passive disk
arrays.
• Prevent multipathing for a specific device.
• Disable a specific 110 path.
• Control the DMP restore daemon.
2-2 VER/TAS Storage Foundation 5.0 for UN/X: Maintenance

VxVM Architecture
User Applications
File Operating System
Block Device Switch [dak]
Character Device Switch (rdsk)
VxVM Config
Databases
Managing Components in the VxVM Architecture
VxVM Architecture
VxVM is a device driver that is placed between the UNIX operating system and
the SCSI device drivers. When VxVI'v1 is running. UNIX invokes the VxVM
device drivers instead of the SCSI device drivers. YxVM determines which SCSI
drives are involved ill the requested I/O and delivers the I/O request to the drives.
VxVM Daemons
YxYM relies on the following constantly running daemons for its operation:
vxconfigd- The VxVM configuration daemon maintains disk and group
configurations. communicates configuration changes to the kernel. and
modifies contigurution information stored on disks. When a system is booted.
the vxdctl enable command is automatically executed to start
vxconfigd. YxVM reads the /etc/vx/volboot file to determine disk
ownership and automatically imports disk groups owned by the host.
vxiod The VxYM 1/0 daemon provides extended 1/0 operations without
blocking calling processes.Several vxiod daemons arc usually started at boot
time. and they continue to run at all times.
vxrelocd~~vxrelocd is the hot-relocation daemon that monitors events
that affect data redundancy. If redundancy failures are detected. vxrelocd
automatically relocates affected data from mirrored or R!ID-5 subdisks to
spare disks or other free space within the disk group.
~~~~~- --~--~~----
Lesson 2 ManagingDevicesWithinthe VxVM Architecture 2~3
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VxVM Configuration Database
• Contains all disk, volume, plex, and subdisk
configuration records
• Is stored in the private region of a VxVM disk
• Is replicated to maintain a copy on multiple disks in
a disk group
- VxVM maintains an appropriate number of active
copies per disk group.
- Copies are stored across enclosures to maximize
redundancy.
• Is updated by the vxconfigd process
VxVM Configuration Database
The Vx VM configuration database stores all disk. volume. plcx. and subdisk
configuration records. The vxconf ig device (/ dev/vx/ conf ig) is the
interface through which all changes to the volume driver state are performed. This
device can only be opened by one process at a time. and the initial volume
configuration is downloaded into the kernel through this device.
The coufigurution database is stored in the private region ofa VxVM disk. Each
disk that has a private region holds an entire copy of the configuration database for
the disk group. The size of the configuration database for a disk group is limited by
the size of the smallest copy of the configuration database on any of its member
disks.
Tile VxVM configuration is replicated within the disk group to protect against loss
of the configuration in case of physical disk failure. vxconf igd actively
monitors live or more copies of the configuration database for each disk group.
VxYM balances their locations based on the number of controllers. targets and
disks in the disk group.
With VxVM 3.2 and later. VxVM configuration copies are placed across the
enclosures spanned by a disk group to ensure maximum redundancy across
enclosures,
The vxconf igd configuration daemon. is the process that updates the
configuration through the vxconf ig device. The vxconf igd daemon was
designed to be the sole and exclusive owner ofthis device.
2-4
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Displaying VxVM Configuration Database Information
ivxdg list acctdg
Group: acctdg _ .. _
~gid: . 1023996467.1130. trainsrCOnfi9Uration
Impo r t= Ld . 0.1129 database size
config copy 1 len=48144 state=clean online
config disk c1t1dOs2 copy 1 len=48144 state=clean online
config disk c1t2dOs2 copy online
config disk c1t3dOs2 copy 1
config disk c1t9dOs2 copy
config disk c1t10dOs2 copy 1 online
config disk c1t11dOs2 copy 1
log disk c1tOdOs2 copy 1 1en=7296
log disk c1t1dOs2 copy 1 len=7296
iNot active "I
copies:
config:
Displaying Disk Group Configuration Data
To display the status of the configuration database for a disk group:
vxdg list diskgroup
Ifno disk group is specified, information from all disk groups is displayed in an
abbreviated format. When you specify a disk group. a longer format is used to
display the status of the disk group and its configuration.
In the example, live disks have active configuration databases (online). and two
disks do not have an active copy of the data (disabled). The configuration
database for a disk group is the size of the smallest private region in the disk group.
Log entries are on all disks that have databases. The log is used by the VxVM
kernel to keep the state of the drives accurate if the database cannot be kept
accurate (for example, if the configuration daemon is stopped).
By default. for each disk group, VxVM maintains a minimum of live active
database copies on the same controller. In most cases. VxVM also attempts to
alternate active copies with inactive copies. In the example. clt3dO and clt9dO
are disabled. If different controllers are represented on the disks in the same disk
group, VxVM maintains a minimum of two active copies per controller.
In the output on the slide, the Configuration database size (pe rml en«) is next to
a field named f r e e«. The free= field can be used to check how fast the
configuration database is filling lip so that action can be taken before the disk
group runs out of database space.
lesson 2 Managing Devices Within the VxVM Architecture 2-5
Copyright '," 2006 Symanter Corporancn. ,.11nallis reserved

Displaying Disk Header Information
The terms displayed in the output oi'vxdisk list include:
Term Description
f----------+-
Full LNIX de ice nameotdiskDevice
Device name used by VxVM to refer to the physical disk
type Method of placing the disk under VxVM control
~------------4------------------------------------------------
devicetag
hostid Name of system that manages the disk group (If blank, no host is
currently controlling this group.)
Disk group name and internal ID
disk VM disk media name and internallD
info
group
flags
Disk fonnat. private region offset, and partition numbers for
public and private regions
------------------------
Settings that describe status and options till' the disk
Paths for block and character device tiles of the public region "I'
the disk
pubpaths
iosize The iosize range that the disk accepts
version Version number of header format
public,
private
Partition (slice) number. offset trorn beginning of the partition.
length of the partition. and disk offset
2--6
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config priv 000256-048207 [047952] :copy=Ol
offset=000192 enabled
log priv 048208-055503 [007296] :copy=01
offset=OOOOOOenabled
lockrgn priv 055504-055647[000144] :part=O
offset=OOOOOO
configuration
database copies,
logs, and lock
;-i="7'===~=:;;;;;:7':~:::::7.~;;;;;;;;;:;;;;;;;;;;~~Last update to the private region
and location of header (sector 0)
and offset to header copies
~~~~"":~~=-r.~7'Z''1''Trr----1 (sector 240)
Defined regions:
config priv 000048-000239 [000192] :copy=01 Location of
offset=OOOOOOenabled
Multipathing information:
numpaths: 2
cltOdOs2 state=enabled
c2tOdOs2 state=disab
The following is a continuation of vxdi sk 1 i st output descriptions:
Term Description
update Date, time, and sequence number ofthe last update to the private
ssb region
headers Offset to two copies of the private region header
configs Number of configuration database copies kept in the private
region
logs Number ofkerncllogs kept in the private region
Defined Location ofconfiguration databases, kernel logs, and lock regions
regions in the private region
Because the database or logs can be split, there can be multiple
pieces. Therefore, the otlset is the starting location within the
private region where this piece of the database begins. Copy
represents the copy of the database to which this piece belongs.
Multipathing ltdynamic multipathing is enabled and there are multiple paths to
Lnf orrna t i on the disk, this item shows information about the paths and their
status.
Lesson 2 Managing Devices Within the VxVM Architecture 2-7
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Disk Types and Disk Formats
Disk types and formats include:
auto indicates that when the vxconf igd daemon has been started. YxYM
automatically COli figures a disk accessrecord for the disk basedon a list of
known disk device addressesobtained trom the operating system. Auto-
configured disks arc displayed with their type aud qualified by their format.
For example, auto: cdsdisk indicates an auto-configured disk that is
formatted as a cross-platform data sharing (CDS) disk that is suitable lor
moving between different operating systems. This is the default format lor
most disks on a system, hut not lor hoot. root, or swap disks.
If a disk is automatically configured by YxYM as a simple or sliced disk, you
will seedisk types and formats, such as auto: simple and auto: sliced.
auto:none indicates that the disk is not Iormaucd lor YxYM.
cdsdisk indicates that the public and private regions are contiguous on the
same partition and suitable lor moving between different operating systems.
sliced indicates that the public and private regions are separatepartitions.
none indicates that there an: no public or private regions on the disk.
VxVM Disk Types and Formats
• auto: Automaticaffy configured by VxVM
auto: cdsdisk (Default for 4.x and higher)
• auto:simple
• auto: hpdisk (Only on HP-UX)
• auto:none
• cdsdisk: Public and private regions are contiguous on the
same partition and suitable for moving between different
operating systems.
• sliced: Public and private regions are on separate partitions.
• hpdisk: HP-UX specific disk format is used for system disk
and before version 4.x.
• none: There are no public and private regions.
Notes:
You can change the default format by using the vxdiskadmoption.
"Change/Display the default disk layouts" or in /etc/vx/disk.
Non-boot sliced disks can be converted to CDS disks by using the
vxcdsconvert command.
2-8 VER/TAS Storage Foundation 5.0 for UN/X: Maintenance
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,a",
VxVM Configuration Daemon
vxconfigd:
Maintains the configuration database
Synchronizes changes between multiple requests,
based on a database transaction model:
symantec.
All utilities make changes through vxconfigd.
Utilities identify resources needed at the start of the
transaction.
Transactions are serialized, as needed.
Changes are immediately reflected in all copies.
Does not interfere with access to data on disk
Must be running for changes to be made to the
configuration database
If vxconfigd is not running. VxVM operates, but configuration
changes are not allowed and queries of the database are not
possible.
The VxVM configuration daemon must be running in order for configuration
changes to be made to the VxVM configuration database. Ifvxconfigd is not
running, VxVM operates properly. but configuration changes are not allowed and
queries of the database arc not possible.
The vxconf igd daemon synchronizes multiple requests and incorporates
configuration changes based on a database transaction model:
All utilities make changes through vxconf igd.
Utilities must identify all resources needed at the start of a transaction.
Transactions arc serialized. as needed.
Changes are immediately reflected in all copies of the configuration database.
The vxconf igd daemon does nut interfere with user or operating system access
to data on disk.
Controlling the VxVM Configuration Daemon
Copynght@,2006 Symaf1ll'!i; Cocooranoo. All flqms reserv"d
2-9Lesson 2 Managing Devices Within the VxVM Architecture

VxVM Configuration Daemon
• vxconfigd reads the kernel log to determine
current states of VxVM components and updates
the configuration database.
• Kernel logs are updated even if vxconfigd is not
running. For example, upon startup, vxconfigd
reads the kernel log and determines that a volume
needs to be resynchronized.
• vxconfigd modes:
- Enabled Normal operating state
- Disabled Most operations not allowed
Booted Part of normal system startup
while acquiring the boot disk group
vxconfigd Modes
vxconfigd reads the kernel log to determine current states ofVxVM
components ami updates the configuration database. Kernel logs arc updated even
ifvxconfigd is not running. For example, upon startup, vxconfigd reads the
kernel log and determines that a volume needs to be rcsynchronizcd.
vxconf igd operates in one of three modes:
Enabled
Enabled is the normal operating mode in which most configuration operations
arc allowed. Disk groups arc imported. and Vx"M begins to manage device
nodes stored in / dev /vx/ dsk and / dev /vx/ rdsk.
Disabled
In the disabled mode, most operations arc not allowed. vxconf igd docs not
retain configuration information lor the imported disk groups and docs not
maintain the volume and plcx device directories. Certain failures, most
commonly the loss of all disks or configuration copies in the boot disk group,
cause vxconf igd to enter the disabled state automatically.
Buotcd
The booted mode is part of normal system startup. prior to checking the root
file system. The booted mode imports the boot disk group and waits tor a
request to enter the enabled mode. Volume device node directories arc not
rnauuaincd, because it may not be possible to I rite to the root file system.
Copyngtll "::. 2006 Swnantec Corporation All rights reservec

~m
Managing the VxVM Configuration Daemon
Use vxdctl to control vxconfigd.
vxdctl mode Displays vxconf igd status
vxdctl enable Enables vxconfigd
vxdctl disable Disables vxcon f igd
vxdctl stop Stops vxconfigd
vxdctl -k stop Sends a kill - 9
vxconfigd Starts vxconfigd
vxdctl license Checks licensing
vxdctl support Displays version information
The vxdctl Utility
symantec.
vxconf igd is invoked by startup scripts during the boot procedure. To manage
some aspects ofvxconf igd, you can use the vxdct 1 utility.
Displaying vxconfigdStatus
To determine whether the configuration daemon is enabled. you use the vxdct 1
mode command. This command displays the status of the configuration daemon,
If the configurauon daemon is not running. it must be started in order to make
configuration changes. Disk failures arc also configuration changes, but there is
another way of tracking them if the daemon is down (kernel logs).
Enabling vxconfigd
If vxc on f igd is running, but not enabled, you use vxdct 1 enable to enable
the configuration daemon. This command forces the configuration daemon to read
all the disk drives in the system and to set up its tables to reflect each known drive.
When a drive fails and the administrator fixes the drive. this command enables
YxYM to recognize the drive.
Disabling vxconfigd
To prevent configuration changes from occurring, you can disable the daemon by
using vxdctl disable.
vxconf igd records all commands executed. whether through the YEA or the
CLI. These commands are stored in /var/adm/vx. The veacmdlog tile
records YEA commands and the cmdlog tile records ell commands.
Lesson 2 Managing Devices Within the VxVM Architecture
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2-11

syrnantec
This host ID is used to ensure that two or more hosts that can access disks on a
shared SCSI bus do not interfere with each other in their use of those disks. This
host ID is important in the generation of unique ID strings that arc used internally
lor stamping disks and disk groups.
The volboot liic also contains the name of the system-wide default disk group if
this has been configured. If the boot disk is under V-xVM control, the vol boot
file also contains the name of the boot disk group to which the boot disk belongs.
Caution: Never edit the volboot file manually. If you do so. its checksum is
im alidated.
The volboot File
/etc/vx/volboot contains:
• The host 10that is used by VxVMto establish ownership of
physical disks .
• The values of defaultdg and bootdgif these values
were set by the user
Caution: Do not edit volboot, or its checksum is invalidated.
To display the contents of volboot:
vxdctl list
To change the host 10in volboot:
vxdctl hostid newhostid
vxdctl enable
To re-create volboot:
vxdctl init llostid
Note: The hostid field in /etc/vx/valboot is not returned by the
UNIX hostid command, but rather by the hostnamecommand.
Managing the volboot File
Viewing the Contents of volboot
To view the decoded contents of the vol boot file:
vxdctl list
volboot file
ve rs i on : 3/1
seqno: 0.1
cluster protocol version: 70
hostid: trainl
Curyroqlll lO[)6 Svm.sruec Curp'H,11I011 All nor.ts reserveo

symaniec
Device Discovery Layer (DOL)
vxdiskconfig (Solaris only)
vxdisk scandisks
vxdctl enable
User process level
Device discovery is the
process of locating and
identifying disks
attached to a host.
Kernel process level
VxVM Kernel
Device discovery occurs
automatically whenever you
add a new disk array.
Discovering Disk Devices
What Is Device Discovery?
Device discovery is the process of locating and identifying the disks that are
accessible to a host. YxYM 3.2 and later features. such asdynamic multipathing
(DMP). depend on device discovery. Device discovery enables you to dynamically
add support for disk arrays from a variety of vendors without rebooting the system.
Discovering and Configuring Disk Devices
To dynamically discover new devices, use the vxdiskconf ig utility. This
utility scans for disks that were added since YxYM's configuration daemon was
last started and dynamically configures the disks to be recognized by YxYM. The
vxdiskconf ig utility invokes OS utilities, such as devf sadmon Solaris, to
ensure that the OS recognizes the disks. vxdi skconf ig then invokes vxdct 1
enable, which rebuilds volume node directories and the DMP internal database
tu reflect the new state of the system.
DOL enables YxYM to use more descriptive names when using enclosure-based
naming, for example. emcO_1 rather than Di sk_l.
Note: The vxdi skconf ig utility docs nut exist on IIP-UX.
Copynqbt ~~ 2006 Syrnantec Corporal Ion II! nqhts reserven

Adding Support for a New Disk Array
With V x VM version 3.1 and later. to add support for a new type of disk array that
is developed by a third-party vendor, you must add vendor-supplied libraries by
using plauorm-spccific package installation commands. The new disk array docs
not need to be connected to the system hen the package is installed. You may
need to scan tor new devices by issuing plauonn-spccilic commands. Theil run
vxdctl enable to ensure that VxVM updates the device list.
Adding Disk Array Support
• To add support for a new type of disk array, add vendor-
supplied libraries. For example:
pkgadd -d /edrom/pkgdir SEAGTda (Solaris)
swinstall -5 /edrom/depotdir SEAGTda (HP-UX)
installp -ae /edrom/pkgfile SEAGTda (AIX)
rpm -ihv /edrom/pkgdir SEAGTda,rpm (Linux)
Scan for new devices:
vxdetl enable
- This command invokes vxconfigd to scan lor all disk devices,
updates the device list, and reconligures DMP.
- You do not need to reboot the host.
Note: VxVM supports many arrays "out-of-the-box."
See vxddladm listsupport lor a complete list.
To remove support for a disk aITaY. you remove the vendor-supplied library
package by using the OS-spcci lie command. For example, to remove support lor
the SEAGTda disk array:
Sularis
Removing Support for a Disk Array
pkgrm SEAGTda
HP-UX
swremove SEAGTda
AIX
I.iIlUX
installp -u SEAGTda
rpm -ev SEAGTda
Ir the arrays remain physically connected to thc host alter support has been
removed. they arc listed in the OTHER_DISKS category. and the VOIUllh:S remain
available.
2-14 VERITAS Storage Foundation 5. afor UNIX: Maintenance
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svmantcc
You can use the vxdisk scandiskscommand to scan
part of the OS device tree, as follows:
• Discover newly added devices previously unknown to VxVM:
vxdisk scandisks new
• Discover fabric devices:
vxdisk scandisks fabric
• Scan for the specific devices:
vxdisk scandisks device=cltldO,c2t2dO
• Scan for all devices except those that are listed:
vxdisk scandisks !device=cltldO,c2t2dO
• Scan for devices that are connected to logical or physical
controllers:
vxdisk scandisks ctlr=cl,c2
• Discover devices that are connected to the specified physical
controller:
vxdisk scandisks pctlr=/pci@lf,4000/scsi@3/
Partial Device Discovery
VxVM supports partial device discovery where you can include or exclude sets of
disks or disks attached to controllers from the discovery process. Partial device
discovery reduces redundant discovery operations by scanning only a part of the
OS device tree.
The vxdisk scandisks command rescansthe devices in the OS device tree
and triggers a DMP rcconfiguration. You can specify parameters to vxdi sk
scandisks to implement partial device discovery.
Ccpynqht r 2006 Svruantec Corporauon All nqtus reserved

Managing Multiple Paths to Disk Devices
The dynamic multipathing (OMP) feature or Vx VM provides greater reliability
and performance for your system by enabling path Iailovcr and load balancing.
Dynamic Multipathing (DMP)
DMP: A method VxVM uses to manage two or more
hardware paths to a single drive
(?!Il.......,ru••• !!H:],
( Fibre Channelswitche~/ j
Dynamic muhipathing is the method that VxVM usesto manage two or more
hardware paths directing 1:0 to a single drive. VxVM arbitrarily selects one ofthe
two namesand creates a single del ice entry. and then transfers data across both
paths to spread the 1:0.
V,VM detects multipath systems by using the universal world-wide device
identifiers (WWD IDs) and manages mulupaih targcts. such as disk arrays. which
define policies for using 1I10rcIIJ:.lnone p.uh.
1=
Host I
• Mapped
==>by DMP
Single OMP
Metanode
Benefits or DM P include:
High availabitity
DMP provides greater reliability using a path Iailovcr mechanism. When one
connection to a disk is 1051.the system coniinucs to accessthe critical data over
the other sound connections 10 the disk until you replace the railed path.
Improved performance
DMP provides greater I/O throughput by balancing the I/O load uniformly
across multiple I/O paths to the disk device.
2-16
IfBcsiOILfBCBil~
rnn1IIIIIIb~~~o;ure
LOiskis disk15 or disk27,
dependingon the path.
What Is Dynamic Multipathing?
Benefits of DMP
Copvnqnt ;:; 2006 Syrnamec Corpcranon All rights reSf'rved

'symanlCC.
Types of Multiported Arrays
Active/Active I
•
Active/Passive If
I Path2
I Passive
I Path
+- (Secondary)
Pathl Path2 Pathl
Active
Path
(Primary)
Active
Path
Active
Path
Used for:
• Load balancing
• Path failover
Used for path
failover only
What Is a Multiported Disk Array?
A multiported disk array is an array that can be connected to host systems through
multiple paths. The two basic types of multiported disk arrays are:
Active/active disk arrays
Active/passive disk arrays
For each supported array type, V.xVM usesa multipathing policy that is based on
the characteristics of the disk array.
Active/Active Disk Arrays
Active/active disk an'ays permit several paths to be used concurrently for 110.With
these arrays, DMP provides greater I/O throughput by balancing the I/O load
uniformly across the multiple paths to the disk devices. If one connection to an
array is lost, DMP automatically routes I/O over the other available connections to
the array.
Active/Passive Disk Arrays
Active/passive disk arrays permit only one path at a time to be used for 1/0. The
path that is used for I/O is called the active path. or primary path. An alternate
path, or secondary path. is configured for use in the event that the primary path
fails. If the primary path to the array is lost. DMP automatically routes I/O over the
secondary path or other available primary paths.
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syrnantec
Setting 1/0 Policies and Path Attributes
To change the 1/0 policy for balancing the 1/0 load across
multiple paths to a disk array or enclosure:
vxdmpadm setattr enclosure enc name iopolicy=policy
• adaptive
• balanced
• minimumq
• priority
• round· robin
• singleactive
To set path attributes for a disk array or enclosure:
vxdmpadm setattr path path_name pathtype=type
• active • primary
• nomanual secondary
• nopreferred • standby
• preferred
Setting the 1/0 Policy for an Enclosure
Alter analyzing statistics. you can use the vxdmpadm setat tr command with
the iopolicy option to change the 1/0 policy for balancing the 110load across
multiple paths to a disk array or enclosure.
You can set policies loran enclosure (Iorcxumplc. HDSOI). for all enclosures ola
particular type (for example. HDS). or for all enclosures ora particular array type
(AlA lor active.active. or Ail' for active/passive).
adapti ve automatically determines the paths that have the least delay and
schedules I/O Oil paths that arc expected to curry a higher load.
balanced takes the track cache into consideration when balancing I/Oacross
paths.
minimumq sends 110on paths that have the minimum number of 1/0 requests
in the queue. This is suitable lor low-end disks or .IBODs where a signi Iicant
track cache does not cxist.
priori ty assigns the path with the highest load carrying capacity as the
priority path.
round-robin sets a simple round-robin policy tor 1/0.
singleac ti ve channels liO through the single active path.
To display the current I/Opolicy:
vxdmpadmgetattr enclosure enclosure name iopolicy

Setting Path Attributes
You can set the following attributes of the paths to an enclosure or disk array by
using the command:
vxdmpadmsetattr path path_name pathtype=type
active changes a standby path to active.
nomanual restores the original primary or secondary attributes of a path.
nopreferred restores the normal priority of the path.
preferred [priori ty=N] specifies a preferred path and optionally
assigns a priority value to it. This indicates a path that is able to carry a higher
I/O load. The priority value must be an integer greater than or equal to I.
Larger priority values indicate a greater load carrying capacity.
,,"ote: Marking a path as a preferred path does not change its I/O load
balancing pol icy,
primary assigns a primary path for an Active/Passive disk array.
secondary assigns a secondary path for an Active/Passive disk array.
standby marks a path as not available for normal I/Oscheduling. This path
is only invoked if there are no active paths available for 110.
See the 1'ERITAS 1'olume MOl1ager Administrator 's Guide and the
vxdmpadm (1m) manual page for more information.
Copyr,ght s: 2006 Symantec Corporation All nqhts resr,rved
2-19

Displaying 1/0 Statistics for Paths
syrnantec
1. Enable the gathering of statistics:
vxdmpadm iostat start [memory=sizeJ
2. Reset the I/O counters to zero:
vxdmpadm iostat reset
3. Display the accumulated statistics for all paths:
vxdrnpadrn iostat show all
cpu usage = 7952us
OPERATIONS
per cpu memory = 8192b
BYTES AVG TIME(ms)
PATHNAME
cOtOdO
c2t1l8dO
c3 t1l8dO
READSWRITES READSWRITES
1088 557056 0
READS WRITES
0.009542 0.000000
0.001194 0.000000
0.000000 0.000000
87
o
44544
o
• The displayed statistics can be filtered by path name, DMP
node name, and enclosure name.
• You can also specify the number of times to display the
statistics and the time interval.
Displaying 1/0 Statistics for Paths
You can use the vxdmpadmiostat command to gather and display JiO statistics
1'01' a specified DMP node, enclosure, or path.
The statistics that arc displayed arc the CPU usage and amount 01' memory pCI'
CPU used to accumulate statistics. the number 01' read and write operations, the
number ofblocks read and written. and the average time in milliseconds pc:r read
and write opcrat ion.
The interval and count attributes may be used to specify the interval in seconds
between displaying the I/O statistics. and the number of lines to be displayed. The
actual interval may be smaller than the value specified if insufficient memory is
available to record the statistics.
2-20 VER/TAS Storage Foundation 5.0 for UNIX. Maintenance
Cunynqlu '<:U06 Swuarnec Corpcrauon All nqnts reserved

IPreventing DMP for a Device m;--------
If an array cannot support DMP, you can prevent
multipathing for the device by using vxdiskadm:
~~~en~ multipathing/s~press d~~ces ~rom VX~~S Vie~
Allow multipathing/Unsuppress devices from VxVM's Vie~
List currently suppressed/non-multipathed devices
IWarning: I
If you do not prevent DMP for unsupported arrays:
Commands like vxdisk list show duplicate sets of disks as
ONLINE, even though only one path is used for 1/0.
Disk failures can be represented incorrectly.
Preventing Multipathing for a Device
If you have an array that cannot support the use ofDMP, or if you want to use
Sun's Alternate Pathing driver with Vx VM. you can suppress DI'vIP for some or all
devices by using the vxdiskadm menu. Suppressing DMP for a device prevents
multipathing without removing the DMP layer.
It is important for you to suppress DMP for devices that do not support OM!'. If
you do not prevent DMP for unsupported arrays:
A VxVM command, such as vxdisk list, shows duplicated sets of disks as
ONLINE for each path, even though the command is only using one path for
110.
Disk failures can be represented or displayed incorrectly by VxVM if DM!' is
running with an unsupported, unsuppressed array.
To manage the devices that participate ill DMP. you call use vxdiskadm.
Copyright '$ 2()06 Syrnantec Corporation 111nonts reserved
2-21

syrnanrec
Preventing DMP for a Device
When you select the option to prevent multipathing in the
vxdiskadm main menu, you have these choices:
,
I,i. suppre-;;'';ii' paths th;ough a controller from ]
. VxVM's view
Suppress a path from VxVM's view
Suppress disks from VxVM's view by specifying a
VID:PID combination
Su resa all but one aths to a di.~s~k ~
Prevent multipathing of all disks on a controller
l __ .:::by£-V:;X::.VM:.::.. •• _
Prevent multipathing of a disk by VxVM
Prevent multipathing of disks by specifying a
VID:PID combination
List currently suppressed/non-multipathed devices
Similar choices exist when you reinclude devices for DMP.
Excluding Devices from Multipathing
When you select the option to prevent mulupathing in the vxdi skadmmain
menu, the Exclude Devices submenu is displayed.
Both of the following options send the command vxdmpadmdi sable to the
kernel:
The option "Suppress all paths through a controller from VxVM's view"
coutinucs to allow the I/O to use both paths internally. Aller a reboot, vxdisk
1i s t dues not show the suppressed disks.
"Prcvcnt multipathing of all disks on a controller by VxVM" docs not allow
the l.O to use intcrnal muliipathiug. The vxdisk list command shows all
disks as ONLINE. This option has no effect on arrays that arc not performing
dynamic multipathing or that do not support VxVM DM!'.
Including Devices for Multipathing
Fur previously excluded devices. if you later decide that you want to rcincludc the
device in muluparhing. then you select the vxdiskadm option "Allow
mulripathing.Unsupprcss dcv iccs lrom VxVM's view." A similar set of options is
available in the Include Devices submenu.
2-22
Copvnqht " 20!)6 Syrnantec Corpo-auon All r'lj~lls reserved
VERITAS Storage Foundation 5.0 for UNIX.' Maintenance

You can disable 1/0 to a controller to perform
maintenance, for example:
• To replace a system board
• To test path failover
Use the following commands:
• To disable 1/0 to a particular controller:
vxdmpadm disable ctlr=ctlI~name
• To disable 1/0 to a particular enclosure:
vxdmpadm disable enclosure=enc_name
• To reenable 1/0 to a particular controller:
vxdmpadm enable ctlr=ctlr_name
In VEA: Select Actions->Disable (or Actions->Enable)
and completethe associateddialog box.
symantcc.
Enabling or Disabling 1/0 to a Controller
By disabling 110 to a host disk controller. you can prevent DMP from issuing 110
through a specified controller. You can disable I/O to a controller to perform
maintenance on disk arrays or controllers attached to the host. For example. when
replacing a system board. you can stop all 110 to the disk controllers connected to
the board before you detach the board.
For active/active disk arrays. when you disable [/0 to one active path, all 1'0
shifts to other active paths.
For active/passive disk arrays. when you disable I/O to one active path. all 110
shifts to a secondary path or to an active primary path on another controller.
You cannot disable the last enabled path to the root disk or any other disk.
On IIP-UX. you can disable the last enabled path to any other disk (without using
the -f (force) option).
When you disable 1/0 to a controller. disk. or path. you override the DMP restore
daemon's ability to reset the path to ENABLED.
When you enable I/O to a controller:
For active/active disk arrays. the controller is used again tor load balancing.
For active/passive disk arrays. the operation results in tailback of I/O to the
primary path.
Enablingor Disablinga Controller: VEA
To disable or enable a controller in YEA. select the controller. select Actions
>Disablc or Actions >Enable. and complete the associated dialog box.
Copvnont 'f 20D6 Svmamer- Corporation All nqhts reservec
2-23Lesson 2 Managing Devices Within the VxVM Architecture

The [)MP restore daemon is an internal process that monitors DMP paths and
automatically enables paths that were previously disabled due to hardware failures
after the paths arc back online.
Controlling the Restore Daemon
The DMP restore daemon is an internal process that
monitors DMP paths. To check its status:
vxdmpadm stat restored
The number of daemons running: 1
The interval of daemon: 300
The policy of daemon: check_disabled
To start the [)MP restore daemon, you use the start restore option in the
vxdmpadm command.
vxdmpadm start restore [interval=intervall
[policy=check_disabledlcheck_alll
The restore daemon unalyzcs the health olpaths every interval seconds. The:
default interval is 300 seconds. Decreasing the interval can adversely affect
performance.
You can specify one oftwo types olpolicics:
If the policy is check_disabled, the restore daemon checks the health of
paths that were previously disabled due to hardware failures and revives them
if they arc back online.
If the policy is check_all, the restore daemon analyzes all paths in the
system, revives the paths that arc back online, and disables the paths that arc
inaccessible.
interval: Frequency of analysis (default: 300seconds)
check disabled: Only checks disabled paths (default)
To change daemon properties:
• Stop the DMP restore daemon:
vxdmpadm stop restore
• Restart the daemon with new attributes:
vxdmpadm start restore interval=400
policy=check_all
I check all: All paths are checked.
Controlllnq Automatic Restore Processes
Starting the DMP Restore Daemon
The default policy is check_disabled.
2-24 VERITAS Storage Foundation 5.0 for UNIX. Maintenance
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symantcc.
Lesson Summary
• Key Points
This lesson described components in the VxVM
architecture and the device discovery process and
described how to administer dynamic multipathing.
• Reference Materials
- VERITAS Volume Manager Administrator's Guide
- VERITAS Storage Foundation Release Notes
- VERITAS Volume Manager Hardware Notes
svmantcc
Labs and solutions for this lesson are located on the following pages:
Appendix A provides complete lab instructions. 'Tab 2: r..LlIu~ing Dc ices 11I:il1
the Y ' I :rL'ililccrllll'," 1',1ic' ,_1,1
Appendix B provides complete lab instructions and solutions, "I ah :: '.;,'!u!iU!h:
M:llll1:2i!l)1 Dcvic •.> Withl11 the ' '1 .vnhirccturc.' pagl 11·: I
Lab 2
Lab 2: Managing Devices Within the VxVM
Architecture
In this lab, you explore the VxVM tools used to
manage the device discovery layer (DOL) and
dynamic multipathing (DMP). The objective of
this exercise is to make you familiar with the
commands used to administer multipathed
disks.
For Lab Exercises, see Appendix A.
For Lab Solutions, see Appendix B.

CllJlYfI!-lot!' 2006 Symamec Cor{lor;;llul"' All fights reserved

Lesson 3
Encapsulation and Rootability

'symankc.
Lesson Introduction
• Lesson 1;Maintaining Data
Consistency
• Lesson 2: Managing Devices Within
the VxVM Architecture
• ~~~~~~i~~yEnCapsulati::_a.:~~ ._~
Process
Overview
symantec.
Topic After completing this lesson, you
will be able to:
Topic 1: Placing the Boot Place the boot disk under VxVM
Disk Under VxVM Control control.
..
Topic 2: Creating an Create an alternate boot disk by
Alternate Boot Disk mirroring the boot disk that is under
VxVM control.
Topic 3: Removing the Remove the boot disk from VxVM
Boot Disk from VxVM control.
Control
3-2 VERITAS Storage Foundation 5.0 for UNIX Maintenance

Placing Disks with Data Under VxVM Control
• On Solaris, encapsulation is the process of
converting partitions into volumes to bring
those partitions under VxVM control.
• On HP-UX, conversion is the process of
enabling LVM physical volumes to be used
byVxVM.
SOlarisl HP-UXI
Placing the Boot Disk Under VxVM Control
What Is Encapsulation or Conversion?
symantcc.
On Solaris. encapsulationis the process of converting partitions into volumes to
bring those partitions under VxVM control. On IIP-UX, conversionis the process
of enabling LVM physical volumes to be used by Vx VM, A Her a disk has been
encapsulated or converted. the disk is handled like an initialized disk,
Placing Disks with Data Under VxVM Control: Solaris
Encapsulation is the process of converting partitions into volumes to bring those
partitions under Vx Vlvl control. For example. if a system has three partitions on
the disk drive and you encapsulate the disk to bring it under VxVM control. there
will be three volumes ill the disk group,
Solaris Encapsulation Requirements
Disk encapsulation cannot occur unless these requirements arc met:
Partition table entries must be available on the disk for the public and private
regions, During encapsulation. you are prompted to select the disk layout. If
you choose a CDS disk layout. then only one partition is needed. However, if
encapsulation as a CDS disk fails. you can specify that a sliced layout be used
instead, in which case you will need two free partitions,
The disk must contain an s2 slice that represents the full disk (The s2 slice
cannot contain a tile system),
2048 sectors of unpartitioned free space. rounded up to the nearest cylinder
boundary. must be available. either at the beginning or at the end of the disk,
Lesson 3 Encapsulation and Rootability
COPYright ~~ 2006 Syrnanter- Corporaucn All nqms reserved
3-3

Encapsulated
data disk
,---._,_ Private region -......--~1~-·-;1----+I homev~ engvol
eng --- '-----
acct -----_'[~ jBW~--.---~~dist ~~
Solaris: Encapsulating a Data Disk
vxdiskadm:
"Encapsulate one or more disks"
Follow the prompts by specifying:
Name of the device to add
Name of the disk group to which the disk will be added
vxencap:
/etc/vx/bin/vxencap -g diskgroup access name
Run the script:
/etc/init.d/vxvm-reconfig access name
Solaris: Reversing the Encapsulation Process
Limitations:
There arc no tools to help with uncncapsulation. (The system disk is an
exception to this.)
Encapsulation should not be attempted if:
Volume layouts have been altered in any way (for example, hot
rclocauon ).
Volumes have mirrors.
The disk has been used for parts of other volumes.
The partition table before encapsulation is stored in:
/etc/vx/reconfig.d/disk.d/device/vtoc
Follow this procedure to encapsulate:
a Stop applications.
b Remove volumes on the disk and take the disk out of VxVM control.
c Re-create thc partition table as provided ill the stored vtoc tile.
d Manually modify /etc/vfstab (itnecessary).
e Reboot or manually mount the partitions and start applications.
CIJPynghl;: 2006 Svmautec Corrorauou All nqtus reservecr

Placing Disks with Data Under VxVM Control: HP-UX
Conversion is the process of enabling LVM physical volumes to be used by
VxVM. You can convert:
Unused physical volumes
Physical volumes in volume groups
Unused
Physical
Volume ~.•..... - ...'..•... '.
U[VXVM Disk Group Ii,y .-k_·4JWJi8L'!£&;;.'*~#Jiik" ~. '
LVM Physical Volumes VxVM Disks
HP-UX: Limitations of LVM Conversion
LVM configurations that you cannot convert to VxVM include:
A volume group with insufficient space for mctadata
A volume group containing the root volume
A volume group containing the lusr file system
A volume group with any dump or primary swap volumes
A volume group disk used in ScrviceGuard clusters
A volume group with any disks that have bad blocks
HP-UX: Converting Unused Physical Volumes
1 View group membership information to ensure that then: is no data on the
LVM disk:
pvdisplay disk_name
pvdisplay /dev/dsk/c4tldO
2 Remove LVM disk information:
pvremove disk_name
pvremove /dev/dsk/c4tldO
3 Initialize the disk for VxVM use,
Lesson 3 Encapsulationand Rootability 3-5
Copyright? 2006 Svrnantar Corporation All nqtus reserved

UP-LJX: Cunverting Volume Groups
vxvmconvert
Volulne Manager SUPPOI"( Operations
Menu: Volume Manager/LvM_Conversion
list
listvg
Allalyze LVM Volume Groups for Conversion
convert LVM Voillme G~oups to VxVM
Roll back tram VxVM to LVM
List disk informatioIl
List LVM Volume Group inforntation
??
Display help about menu
Display help about the menuing system
Ex i t f iorn menusq
Select an operation to perfOrl":
UP-LJX: Conversion PrOC('SS(LV'I to VxV'I)
1 Identify volume groups.
2 Analyze volume groups.
3 l3ack lip LV M data.
4 Plan for new names.
5 Stup applications.
6 Unrnount the file system.
7 Convert volume groups.
8 Make name changes.
9 Restart applications.
10 Customize the configuration.
IIP-LJX: Restoring LVi! Volume Group Cunfiguration
Roll Back Using vxvmconvert
Full LVM Restoration fur the Volume Group
LVM Volume Group VxVM Disk Group
LVM Physical Volumes VxVM Disks
CIlPVflljlllL 2006 Syruantec Corpnratrcu All r.ghts reserved

HP-UX: Roll Back Using vxvmconvert
vxvmconvert Option 3, roll hack from ',',1 to 1.',1
Select Volume Group(s) to rollback:
[<pattern-list>,all,list,listvg,q,?) vg08
Roll back this Volume Group? [y,n,q,?) (default: y)
Rolling back LVM configuration records for Volume Group vg08
Selected Volume Groups have been restored.
Hit RETURN to continue.
Rollback other LVM Volume Groups? [y,n,q,?) (default: n)
UP-lIX: Full L'll Restoration for the Volume Group
To restore LVM internal data:
mkdir /dev/vol group_name
mknod /dev/vol_group_name/group c 64 oxoeoooo
vxdg destroy diskgroup
For each disk in the volume group:
vxdiskunsetup disk_name
vgcfgrestore -F -f pathname/filename raw_device_name
vgimport -s -m pathname/mapfilename vol grp_name
raw device name
vgchange -a y vol group_name
To restore user or application data:
mount -F fstype /dev/vol group_name/lvname /mount po~nt
frecover -r -f /dev/rmt/cOtOdOBEST
------------------------------------------------------
Copyrlgt1~, 2()06 Syrn"lnl€r Corporation 111nor.ts reserved
3-7

What Is Rootability?
Rootability is the process of placing the root file system,
swap device, and other file systems on the boot disk under
VxVM control.
On Solaris, you encapsulate the system disk.
Encapsulated
boot disk
II
Partitions are mapped to subdisks
that are used to create the volumes
¥ that overlay the original partitions.
W:---""Sii1l Private region
1Ir---"':!III / ------<
1:? -?i1/usr----------~====~-'------
~-----~;::;~ ~
Note: Only sliced layout is allowed.
What Is Rootability?
Rooiability is the process ofplncing the root file system. swap device, and other
file systems on the boot disk under VxVM control.
Solaris
On Solaris, VxVM converts existing partitions ofthe boot disk into VxVM
volumes. The system can then mount the standard boot disk file systems (that is.
/, /usr. ami so 011) from volumes instead of disk partitions.
Boot disk encapsulation has the same requirements as data disk encapsulation, but
requires two Ircc partitions (for the public and private regions). When
encapsulating the boot disk. you can create the private region from tile swap area,
which reduces the swap area by the size otthc private region. The private region is
created at the beginning of the swap area. and the swap partition begins one
cylinder from its original location.
When creating new boot disks, you should start the partitions on the new hoot
disks on the next cylinder beyond the 2048 default used tor the private region.
ur-ux
011 HP-UX. rootability is carried out by creating a coJlY of the system disk on
another VxVM disk.
Copvnqhr 'C' 20U6 Svmantec Co-poianon 111nqnts reserved
VERITAS Storage Foundation 5.0 for UNIX: Maintenance3-8

symantec.
Why Put the Boot Disk Under VxVM Control?
On Solaris:
• You should encapsulate the boot disk only if you plan
to mirror the boot disk.
• Benefits of mirroring the boot disk:
-Enables high availability
-Fixes bad blocks automatically (for reads)
-Improves performance
• There is no benefit to boot disk encapsulation for its
own sake. You should not encapsulate the boot disk if
you do not plan to mirror the boot disk.
On HP-UX:
Single storage virtualization tool for system disk and
data disks.
It is highly recommended that you encapsulate and mirror the boot disk. Some of
the benefits of encapsulating and mirroring root include:
High availability
Encapsulating and mirroring root sets up a high availability environment for
the boot disk. Ifthe boot disk is lost. the system continues to operate on the
mirror disk.
Bad block revecturing
If the boot disk has bad blocks. then YxYM reads the block from the other disk
and copies it back to the bad block to fix it. SCSI drives automatically fix bad
blocks on writes, which is called bad Mock rvvcctoring.
Improved performance
By adding additional mirrors with different volume layouts. you can achieve
better performance. Mirroring alone can also improve performance if the root
volumes arc performing more reads than writes, which is the case on many
systems.
Why Put the Boot Disk Under VxVM Control?
When Not to Encapsulate Root
If you do not plan to mirror root. then you should not encapsulate it. Encapsulation
adds a level of complexity to system administration, which increases the
complexity of upgrading the operating system.
Copyngm t; :'001'; Syruamec Corpoeauon 111r.qhrs reserved
3-9

Limitations of the VxVM Boot Disk
• Placing the boot disk under VxVM control adds
steps to OS upgrades on Solaris platform.
• A system cannot boot from a boot disk that spans
multiple devices.
• Never grow or change the layout of boot disk
volumes. These volumes map to a physical
underlying partition on disk and must be
contiguous.
HP-UX Note: HP-UX supports OS installations on a
VxVM disk. However, the version of VxVM that is
installed from the HP-UX installation media for 11iv2
is 3.5.
Limitations of the VxVM Boot Disk
A system cannot boot from a boot disk that spans multiple devices.
You should never expand or change the layout of boot volumes, No volume
associated with an encapsulated boot disk (r oot.vo l , usr. var. opt. swapvoL,
and so on) should be expanded or shrunk. because these volumes map to a physical
underlying partition on the disk and must be conuguous,
If you attempt to expand these volumes. the system can become unbootublc ifit
becomes necessary to reven back to slices in order to boot the system. Expanding
these volumes can also prevent a successful OS upgrade. and a fresh install can be
required.
Solaris
Additionally. the upgrade_start script (USedin upgrading VxVM to a new
version) may Jail.
Note: You can add a mirror ofa dillcrcut layout, but the mirror is not bootablc.
3-10 VERITAS Storage Foundation 5.0 for UNIX' Maintenance
Copyright! 2006 Symantec Corporation All uqhts reserved

symantec.Th
-File System Requirements: Solaris Only
For root, usr, var, and opt volumes:
• Use UFS file systems. (VxFS is not available until later in the
boot process.)
• Use contiguous disk space. (Volumes cannot use striped,
RAID-5, concatenated mirrored, or striped mirrored layouts.)
• Do not use dirty region logging on the system volumes. (You
can use DRl for the opt and var volumes.)
For swap volumes:
• The first swap volume must be contiguous, and, therefore,
cannot use striped or layered layouts.
• Other swap volumes can be noncontiguous and can use any
layout. However, there is an implied 2-GB limit of usable swap
space per device for 32-bit operating systems.
HP.UXI
File System Requirements for Root Volumes: Solaris Only
To boot from volumes. follow these requirements and recommendations for the
file systems on root volumes:
For the root. usr. var. and opt volumes:
Use lJFS file systems: You must use UFS file systems for these volumes.
because the VERITAS File System (VxFS) package is not available until later
in the boot process when the scripts run in /etc/rc2.d (multiuser mode).
Use contiguous disk space: These volumes must be located in a contiguous
area on disk. as required by the OS. For this reason. these volumes cannot use
striped. RAID-S. concatenated mirrored. or striped mirrored layouts.
Do not use dirty region logging for root or uar: You cannot use dirty region
logging (DRL) on the root and usr volumes. If you attempt to add a dirty
region log to the root and usr volumes. you receive an error.
Note: The opt and var volumes call use dirty region logging.
Swap Space Considerations: If you have swap defined, then it needs to be
contiguous disk space. The first swap volume (as listed in the /etc/vEstab
tile) must be contiguous and. therefore. cannot use striped or layered layouts.
Additional swap volumes can be noncontiguous and can use any layout.
Note: You can add noncontiguous swap space through VxVM. However,
Solaris automatically uses swap devices in a round-robin method. which may
reduce expected performance benefits of adding striped swap volumes.
For 32-bit operating systems. usable space per swap device is limited to 2 GB.
For M-bit operating systems. this limit is much higher (up to :zi,,l - I bytes).
lesson 3 Encapsulation and Rootability
Copynqtu T: 2(J06 Symaruec Cornoranon. 1(1 ••ghlf> reserved
3-11

Volume Requirements: HP·UX
All volumes on the root disk must be in thc disk group that you choose to be the
bootdg disk group.
The names otthc volumes with entries in the LIF LABEL record must be
standvol, rootvol, swapvol, and dumpvol (ifpresent). The names ofthe
volumes for other file systems on the root disk arc generated by appending vol to
the name of their mount point under /.
Any volume with an entry in the LI F LABEL record must be contiguous. Thc
volume can have only one subdisk. and it cannot span to another disk.
The root vol and swapvol volumes must have the special volume usage types,
root and swap respectively.
Only the disk access types auto with hpdisk and simple formats arc suitable
1(lJ" use as Vx VM root disks, root disk mirrors, or as hot-relocation spares for such
disks.
The volumes on the root disk cannot use dirty region logging (DRL).
3-12 VERITAS Storage Foundation 5.0 for UNIX: Mamtenance
Copyright 2006 Svmautec Corroranon 111nylliS reserve-s

Before Placing the Boot Disk Under VxVM Control
Plan your rootability configuration:
Plan your rootabjlltv conflguration. bootdg is a system-wide reserved disk
group name that is an alias for the disk group which contains the volumes that arc
used to boot the system. When you place the boot disk tinder VxVM control.
VxVM sets bootdg to the appropriate disk group. You should never attempt to
change the assigned value nfbootdg: doing so may render your system
unbooiable. An example configuration is to place the boot disk into a disk group
named sysdg. and add at least two more disks to the disk group: one for a boot
disk mirror and one as a spare disk. VxVM then sets bootdg to sysdg.
Solaris
Encapsulated Boot disk
boot disk mirror
Spare disks
Enable boot disk aliases. On Solaris. before encapsulating your boot disk. set the
EEPROM variable use -nvramrc? to true. This enables VxVM to take
advantage of boot disk aliases to identify the mirror of the boot disk if a
replacement is needed. If this variable is set to false. you must determine which
disks are bootable yourself
On Solaris, set this variable to true as follows:
On Solaris:
Enable boot disk aliases:
eeprom "use-nvramrc?=true"
• Record the layout of the partitions on the unencapsulated boot disk
to save for future use.
On HP-UX:
Set the primary or alternate boot path from the boot menu or from the
command line:
Main Menu: Enter command or menu: co pa alt path
setboot -p primary_path -a alternace __path
Save the LVM volume group configuration for vgOO.
Before Placing the Boot Disk Under VxVM Control
eeprom "use-nvramrc?=true"
Save the layout of partitions before you encapsulate the boot disk. For
example. on Solaris. you can use the prtvtoc command to record the layout of
the partitions on the unencapsulated boot disk (/ dev / rdsk/ cO t OdOs2 in this
example):
prtvtoc /dev/rdsk/cOtOdOs2
Record the output from this command fur future reference.
Copynqru e. 2006 Syrnantac. Corporanon All nqhts reserved
3-13

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