This document discusses implementing disk-based data protection and recovery. It recommends taking a tiered approach with five layers - application, production, recovery, protection, and archive tiers. The recovery tier is where disk systems would replace tape to provide faster restore times and more frequent backups. For best results, the document advises selecting a single vendor that can provide tightly integrated, modular solutions for each tier built on a common software platform. This comprehensive approach maximizes reliability while minimizing complexity.

1. * DRAFT *
Implementing Seamless Disk-based
Data Protection and Recovery
By Michael S. Mendola,
Sr. Storage Architect
A Mendola White Paper

2. Contents
Introduction 2
Is Disk-based Data Protection New? 2
To Do-it-Yourself or Not 3
The Key to Choosing and Planning
for Disk-based Data Protection and
Recovery 3
Implementation 5
Summary 5
Introduction
Have you already considered migrating to a
disk-based backup and recovery method?
Are you already somewhere along this path,
or haven’t yet decided that this is even right
for you? In any case, you are about to learn
the most efficient and cost-effective way of
planning for and bringing disk-based backup
and recovery into your IT environment.
Data protection and recovery have been a
major IT challenge for many years. It has
been said by experts that backup may
account for more than 50% of IT systems
administration time. Further, backing up
data to tape takes so much time and attention
that the capability to actually be able to
restore from backup data usually goes
untested - until that data is needed.
Many large IT shops are considering or
already enhancing their backup strategy with
new disk-based options. By moving to the
capabilities of disk, enterprises can
complement their tape backup strategies to
achieve faster and more reliable backup and
much faster – and more relevant – data
recovery while continuing to use tape for
offsite storage and longer-term archiving.
Is Disk-based Data Protection New?
By now many, if not most administrators of
IT systems in smaller businesses have at
least had the passing thought of
implementing a disk-based data protection
solution. Although the concept is certainly
not new, many quickly find that the myriad
of choices in solutions, methodologies and
vendors (and vendor claims) make the
“goodness” of disk-based backup and
recovery quickly regress into a solution that
is more expensive and at least as unwieldy
to manage as their old tape-based system
was. This is mainly due to realizing too late
that there are many considerations to be

3. taken into account when moving
toward using disk technologies to
protect and recover business-critical
data and systems, especially if there
are one or more remote business
locations which must be considered.
To Do-it-Yourself or Not
The concept of using disk instead of
tape as a “backup target” is fairly
straightforward, and this can be done
while still keeping the legacy tape-
based system intact. Many smaller
shops even start out by just daily
copying their files to one or more
USB drives and then taking the
drives offsite. Others have started to
use online WAN-based service
providers which allow automatic
periodic file backup over the Internet
to a remote vaulting location where
data is protected and restorable at the
file or even disk-image level when
needed. Again, for very, very small
businesses these options may be just
the thing. However, should the
business start to grow, or where there
might come into play external
demands, such as compliance,
varying mandated retention policies,
etc., these methods will quickly
become a major liability which itself
will start to beg for a solution; The
act of changing what has already
been put into place will be much
more costly in time, money,
materials – and disruption - than first
employing, through proper planning
and implementation the best solution
which fits current needs and can then
be made to granularly and
seamlessly scale to accommodate
growing needs or even just shear
changes in requirements.
The Key to Choosing and Planning
for Disk-based Data Protection and
Recovery
For the small-to-medium-sized organization,
the debate on whether disk-based data
protection should be used is pretty-much
over because the benefits far outweigh tape
as the method of production data protection
and recovery. As we have seen, the major
“downside” is to not truly understand how to
go about constructing the vision for, and
then finding the products and services and
vendors to bring disk-based techniques to
life in the most cost-effective and efficient
way, with emphasis on long-term efficacy.
An added benefit of proper planning and
implementation using the right products and
services is that cost reduction and
technology obsolescence avoidance (“future
proofing”) can be had wherever any storage
is used throughout your IT environment –
even if there are one or more remote sites to
consider.
The best way to view all data storage is in a
five-tier hierarchy which provides a more
holistic point-of-view. Below is a diagram
which does just that:

4. The diagram uses five layers to
describe storage and its use. Let’s
briefly examine each layer.
Application Tier
All business computers live here.
What each does is immaterial. From
powerful database servers down to
web servers, to back room file
servers, they all have one major
thing in common: They all write,
read and store data on disk.
Production Tier
This is where all of the primary
storage “lives”. Whether internal,
external direct-attached, SAN-based
or NAS, this is where all of the data
is stored - lifeblood business data,
email, down to the golf outing
JPEG’s and music MP3’s, this is
where it all is – and this is what you
need to backup and hopefully are
able to restore if any of it becomes
unavailable (okay, maybe the
JPEG’s and MP#’s are not that
important).
Recovery Tier
This is the layer where you have
systems which hold copies of the
data on in the Production Tier.
Unfortunately many still use tape
here – this is what you are planning
to replace with a disk-based model.
If you had to restore your most
critical business application data,
there are two main question this
layer must allow you to efficiently
address:
- Recovery Time Objective
(RTO): How long will it take
to get the data restored AND get the
application server up and servicing
requests again? (Using snapshot
technology will recover the data in a
very short time, but unless the disk
snapshot system uses integrated file
system and application preparation
agents, database systems will
perform a data consistency check
which will ADD possibly hours to
finally getting the application server
up and running the business again.
- Recovery Point Objective (RPO):
How “stale” is the data that will be
used to restore from? (note that with
tape the answer is easy: it’s as
“fresh” as the last backup, typically
at least 24 hours old).
POINT: The disk systems in this layer are
key as they must protect, reliably hold and
recover your data to whatever “flavor” of
primary storage failed: internal (data and OS
system boot recovery), DAS, SAN and
NAS). Also, if protecting your data means
moving it offsite to another facility (or
protecting data at remote sites means
sending it back to the main site), replication
would fit here as well. The systems in this
layer should enable open choice for what
storage, storage protocols and network
infrastructure to use - and should best be
vendor neutral. It should allow the use of
the most inexpensive disk possible, even if it
might be recycling decommissioned disk
form the Production Tier. Further, it should
be able make the most efficient use of
network bandwidth if replication will be in
the mix.
Protection Tier
This is the place for tape image (both
physical and virtual) data storage, including
disk-based clones if desired.

5. POINT: ALL first line production
data protection and recovery (with
optimum RTO and RPO “dialed-in”
for each business system) is done
from the Recovery Tier, leaving the
Protection Tier to hold only the
“backups-of-the-backups”.
Archive Tier
It is here where the oldest data which
is still worthy of retaining lives.
Disk storage systems used here
should be of the most cost-effective
and permanent nature (i.e. slowest
access performance, optical, Content
Addressable Storage (CAS),. Data
deduplication systems would fall into
this category as well.
Implementation
As can be seen, stratifying storage
and storage protection and recovery
concepts makes plain the inherent
need for a solid vision and proper
planning and hardware and software
and services vendor selection(s).
There are many vendors, including
your incumbent server and storage
vendor(s), which have their own
disk-based protection and recovery
strategies. These by necessity are
engineered to work best (and
sometimes only with) their main
server and/or storage products suite
and, by nature this will force the
technology/methodology
combination onto the user, resulting
in being more-or-less “locked-in” to
that paradigm.
Just as important to realize is that it
may take multiple vendors to
implement customized solutions at
each layer in the model for your
local and remote organization(s).
Much more rewarding is to select a single
vendor whose sole business is satisfying
each layer in the model with hardware and
software which are specifically designed and
totally integrated as a unit to supply the
features seamlessly. The best scenario is to
have all of the software that drives each
storage system in each layer below the
Application Layer based on a single code
set.
Summary
Disk-based methodologies can simplify,
make more efficient, and most importantly,
much more reliable, the protection and
recovery of your business data. It enables
you to turn from maintaining your data
backup and restore as separate and labor-
intensive operations with often questionable
value toward merging these into a reliable,
rapid and seamless operational environment
which becomes part of your daily production
storage operations. It can also enable
customizable recovery time and recovery
point objectives for each business
application system, giving the ability to
“dial-in” the right mix of solution
capabilities, costs and scaling over time.
The best way to achieve all the “goodness”
of disk-based methodologies is two-fold.
First, seek a tightly integrated modular
solution suite from a single vendor. Further,
the product set should provide components
to cover each layer in the tiered model
which are built on a common code platform.
This approach maximizes product
interoperability and reliability and
minimizes operational complexity.
Second, choose a product and services
provider that has experience and expertise in
this area, especially within the context of the
chosen solution set. Demand a proven
record of expertise in design, planning and

6. implementation of disk-based
methodologies.