Virtual store a nas software solution for v-mware environments

Symantec VirtualStore
A NAS Software Solution for
VMware Environments

White Paper: Storage Management

A NAS Software Solution for VMware Environments

Contents

Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

From SAN to NAS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

The NAS bottleneck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Unbundling NAS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Symantec VirtualStore . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

NAS economics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Use cases and advantages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Adding capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Upgrading SAN resources. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Increasing throughput . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Optimizing desktop delivery. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

High Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Business continuity and disaster recovery. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Snapshots. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Remote and branch offices. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

VirtualStore and Storage Foundation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

VirtualStore in VMware environments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Economy and performance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Manageability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Conclusion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8


Executive Summary
Virtualization is transforming the world’s data centers, driving adoption of Network-Attached Storage (NAS) to simplify
management of VMware® virtual environments. But controller bottlenecks in bundled NAS appliances throttle
performance even at modest storage volumes, and adding controllers to overcome them quickly becomes very expensive.

Unbundled NAS solutions offer the same front-end flexibility, and unlock controller architecture and the storage-facing
back end to deliver highly scalable storage using standard hardware to reduce costs dramatically. Symantec™
VirtualStore, built on Veritas™ Storage Foundation™ from Symantec, offers increased capacity and throughput for virtual
servers and desktops, and adds High Availability, business continuity, policy-based tiered storage, and full integration
with VMware’s own vCenter management solution.

Introduction
Virtualization—with VMware® in the lead—is transforming the world’s enterprise data centers. Governments,
multinational financial conglomerates, and global hosted service providers are using the server and desktop virtualization
to cut the costs of hardware, facilities, power and cooling, and take advantage of new approaches to availability, business
continuity/disaster recovery, and IT management. Analyst firm IDC1 offers perspective on virtualization’s penetration and
growth:

• 2010 is the first year that more than 50% of application instances run in virtual machines (VMs)
• By 2014, more than 23% of new servers will support virtual machines, and more than 70% of newly installed
workloads will run on them
• Virtualized server compound annual growth is forecast at 14%—more than twice the rate of the server market
as a whole

Most large enterprise datacenters already have de facto “virtual first” policies for server deployment. Still, there’s plenty
of room to grow, for example at regional and branch offices, and in fast-emerging areas like private cloud computing and
desktop virtualization.

The next wave of virtualization, like the first, will be driven by economy, performance, manageability and security. But as
virtualization expands outside the datacenter core—closer to employees and customers—Quality-of-Service (QoS) issues
take on more significance, cost pressures grow more severe, and IT organizations face new constraints on their
virtualization initiatives.

From SAN to NAS
Virtualization changes the fundamentals of IT practice2, sometimes in unexpected ways. Storage is a case in point. Virtual
machines consume lots of it, and QoS depends on high performance. Virtual desktops and streaming applications in
particular need high-performance storage to cover unpredictable I/O patterns and worst-case scenarios like boot-up and
login “storms.”
1-International Data Corporation (IDC). Worldwide Market for Enterprise Server Virtualization to Reach $19.3 Billion by 2014, According to IDC (press release). (Framingham, MA. December 6, 2010). http://www.idc.com/
about/viewpressrelease.jsp?containerId=prUS22605110&sectionId=‌null&elementId=null&pageType=SYNOPSIS
2-Galen Schreck. Why Isn’t Server Virtualization Saving Us More? (Cambridge, MA: Forrester Research. January 28, 2009). http://www.vmware.com/files/pdf/technology/
Why_Isnt_Server_‌Virtualization_Saving_Us_More.pdf

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Early versions of VMware ESX required that VMs be stored on fast, expensive Fibre Channel Storage Area Networks
(SANs). But block-level SAN pushes responsibility for file-level storage management onto virtual clients, and Fibre
Channel zoning is not only difficult to manage, but compromises the flexibility and mobility of virtual machines.

Current versions of ESX support simpler, more flexible Network-Attached Storage (NAS) to overcome many of these
limitations at lower initial cost. By using the Network File System (NFS) to deliver a file system as well as block-level
storage, NAS takes care of storage housekeeping. This reduces the burden on virtual clients, so VMware virtual machines
(VMs) run at higher speed. NAS also imposes no penalties for large LUNs, and intelligent solutions allow much more
efficient storage management.

The NAS bottleneck
But the way NAS is bundled and sold complicates—and may even neutralize—its cost advantage. Pre-configured NAS
appliances bundle NAS filers and servers along with storage, constraining scalability, utilization, manageability, and
economy in virtualized IT environments:

• Added capacity bundles in filers and controllers (NAS heads) that raise cost and management complexity
• Raising throughput by adding controllers bundles in filers and storage, raising costs, management burdens, and
underutilized storage assets

In virtualized environments, the first of these is rarely a meaningful constraint. NAS appliances can pair a single filer and
pair of controllers with massive amounts of storage, so growing virtualization environments typically encounter controller
bottlenecks long before they reach their storage limits. In I/O-intensive database, application-streaming, and desktop
virtualization environments, severe throughput constraints may show up at storage volumes as low as 6TB for servers or
30TB for desktops.

NAS filers add significantly to the cost of “raw” storage—and most of it comes from the cost of controllers. Add
management, rack space, and other indirect costs, and it’s clear that using bundled NAS appliances to solve throughput
problems gets expensive fast. As virtualization continues its torrid growth, these NAS price/performance tradeoffs will
impose a significant brake on organizations’ ability to deploy virtualization in new locations and applications.

Unbundling NAS
An ideal storage solution for a growing virtualization environment would combine these elements:

• Front-end simplicity—NAS, to relieve virtual clients of file-level abstraction responsibilities and IT
administrators of complex storage management
• Back-end flexibility—a choice of storage hardware from fast Fibre Channel SAN for high QoS in demanding
scenarios, to commodity storage for routine applications
• Scalable throughput—inexpensive controller hardware that delivers extra NAS heads without bundling in
unnecessary filers and storage
• Economy—off-the-shelf components, competitively-sourced to avoid vendor lock-in and preserve future
flexibility

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• VMware compatibility—full compatibility with VMware High Availability solutions, and with VMware’s own
vCenter™ consoles and utilities for tight integration and a minimum of management complexity

Facing NAS price/performance tradeoffs and obsolescence of large SAN installations in their data center consolidations, a
few large enterprises adapted the Veritas™ Storage Foundation™ Cluster File System from Symantec as an
intermediary—presenting Fibre Channel SAN to the back end and NAS to the front. Their results proved the solution’s
performance and cost-effectiveness. Symantec has since generalized and adapted its customers’ solution, adding
provisioning, caching, and management capabilities, and made it available as Symantec™ VirtualStore.

Symantec VirtualStore is a highly scalable clustered Network File System solution for VMware virtual machines, based on
the proven, industry-leading Veritas Storage Foundation™ Cluster File System from Symantec. VirtualStore unlocks the
flexibility and power of Network Attached Storage architectures from the price/performance constraints of appliance-
based solutions, without compromising the performance, scalability, and High Availability advantages of Cluster File
System. It meets special challenges of virtual infrastructures with new features that rapidly provision virtual servers and
desktops, and clone or boot virtual machines, all through the VMware vCenter™ management console.

Figure 1 illustrates the general configuration of VirtualStore in a VMware environment. The solution comprises these
elements:

1. ESX servers hosting virtual machines that access files over the network using the Network File System protocol
2. A scalable VirtualStore cluster of commodity servers running Cluster File System under Solaris UNIX or Red Hat®
Linux, using standard Network Interface Cards for I/O
3. Back-end storage hardware from a choice of vendors, and technology options that include or combine SAN,
SATA, SCSI (SAS), iSCSI, JBOD commodity storage, and solid-state drives
4. The VMware vCenter management interface plug-in (not shown) integrates VirtualStore storage management
operations into vCenter so that virtual machines—storage and all—may be provisioned, moved, and managed
as complete entities for greater flexibility and simpler operations

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Figure 1: Symantec VirtualStore™ presents highly scalable NFS simplicity and flexibility to VMware virtual machine
environments, while preserving a broad choice of technologies, price points, performance standards, and storage vendor
options.

NAS economics
Price comparisons between NAS appliances and Symantec VirtualStore will depend on hardware costs, network and
storage bandwidth, number, size, and diversity of served images, and all the other factors that define specific use cases.
But in most mainstream applications, VirtualStore offers compelling cost advantages. Consider three “standard”
VirtualStore scenarios using mainstream hardware3, illustrated in Figure 2:

• Comparison case—an extremely light requirement sometimes used as a benchmark for comparisons: 8 NAS
operations per second (op/sec), adequate for acceptable QoS in only the most forgiving use cases
• Desktop virtualization—less demanding due to lighter loads and greater opportunity for cloning and
compression: assumed to consume 25 op/sec per virtual desktop served

3-

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• Server virtualization (for example, data-center consolidation)—the most demanding case, here assumed to
require 100 op/sec per virtual machine for acceptable QoS

Figure 2: The number of virtual machines VirtualStore will support at three performance levels, using standard hardware
and the indicated number of nodes. See text for details.

Figure 2 shows that performance-scaling VirtualStore environments is a matter of adding standard nodes, each configured
using stock components available from competing suppliers. Scaling storage volume means attaching more drives to the
SAN fabric on the back end. VirtualStore, like the Storage Foundation architecture on which it is built, easily manages
heterogeneous storage hardware, so hardware re-use and storage tiering are realistic, low-cost alternatives. Finally, nodes
can be added “hot” for zero business interruption during expansion or maintenance.

In comparisons with VirtualStore, it is worth keeping in mind that NAS appliance alternatives impose recurring expense
and disruption. Depending on organizations’ hardware refresh policies, they will face large-scale “forklift”-style upgrades
of very expensive hardware every few years. Using VirtualStore to disaggregate NAS into stock server and storage
components makes it easier to integrate upgrades into data center refresh cycles, and can completely eliminate the
associated business interruptions.

Use cases and advantages
Symantec VirtualStore unbundled high-performance NAS storage outperforms appliance-based NAS in virtualized
environments in a broad spectrum of use cases.

Adding capacit y
capacity
Symantec VirtualStore offers a cost-effective way to scale storage capacity for VMware servers by adding intelligent
storage arrays or commodity storage as required. Storage Foundation technology includes thin provisioning and storage

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tiering, so VMs consume only the quantity of storage they need, and may be allocated only the quality of storage their
applications require. With no filers bundled with storage, VirtualStore offers nearly perfect linear scaling, and helps
minimize underutilization of storage assets.

Upgrading SAN resources
Upgrading the functionality and manageability of SAN assets in VM environments is a natural application for Symantec
VirtualStore, requiring only software licenses and stock hardware to upgrade even the largest SAN arrays to NFS. Benefits
include elimination of file management overhead from virtual machines, and better VM mobility, without the
complications of Fibre Channel zoning.

Increasing throughput
With a capacity of 64 (software) controllers per filer compared with 2 (typical) to 8 for NAS, VirtualStore excels delivering
cost-effective storage throughput. Using stock server and NIC hardware, a single VirtualStore node has a practical
throughput capacity of about 250 full-throttle ESX servers (at 100 op/sec; see Figure 2).

Optimizing desktop deliver y
Optimizing delivery
Desktop virtualization has special requirements. First, Quality-of-Service requirements are very high: desktop-level
personalization and performance is the key to user acceptance. Second, typical large-scale back-office deployments
generate breathtakingly high traffic during boot- and login- “storms.” Instead of a brute-force solution using expensive
solid-state drives, VirtualStore caches and serves one image copy from the controller’s main memory, retrieving only
difference images—“deltas”—from disk.

High Availabilit y
Availability
VirtualStore offers all the High Availability (HA) features that make Storage Foundation Cluster File System the first choice
for management of large-scale enterprise storage environments. These include fast failover for applications and SAP,
Oracle, Sybase, or Tibco databases, the ability to add or replace servers “hot” in the cluster, eliminating planned downtime
for maintenance or filer/controller upgrades, and NFS active/active failover from all hosts in a VirtualStore cluster.

Business continuit y and disaster recover y
continuity disaster recovery
VirtualStore Campus or Metro Clusters are fully compatible with VMware vMotion, supporting fast migration of running
virtual machines from one site to another with no downtime or user impact, and virtually undetectable backup and
recovery.

Snapshots
Snapshots
VirtualStore includes efficient FileSnap™ technology that allows “on the fly” creation and storage of space-optimized boot
images of virtual machines. These file-level differential snapshots of virtual machine images reference a single golden
template. Deduplication of 80% or more allows provisioning hundreds of virtual machines without excessive storage
consumption.

6


Remote and branch offices
Remote
Virtualization is an excellent way to address utilization issues at remote and branch offices: allocating virtual resources
rather than physical hardware supports multiple applications while keeping IT facilities, expenditures, and management
effort under control. But few smaller offices can justify the expense of high-performance NAS appliances. Stock hardware
and VirtualStore offer a practical alternative that integrates storage more tightly into virtual infrastructure, and simplifies
both local and remote management.

VirtualStore and Storage Foundation
VirtualStore is based on Veritas Storage Foundation from Symantec, a complete solution for managing heterogeneous
online storage. VirtualStore supports Solaris Sparc, and RedHat Linux, as well as a broad set of qualified storage devices
and arrays.

VirtualStore supports efficient, non-disruptive migration from one storage platform to another, and keeps thin-
provisioning environments thin using automated storage reclamation. The solution includes SmartTier, which migrates
data among storage tiers—Fibre Channel, SATA, Solid State, and more—seamlessly and transparently, based on its
business value.

VirtualStore in VMware environments

Economy and performance
conomy performance
In a variety of server and desktop virtualization environments, VirtualStore can help organizations optimize current SAN
storage infrastructure for performance, flexibility, and manageability while reducing capital and operating costs. Free
from the constraints of NAS appliances that bundle storage with throughput-constrained fixed controllers, VirtualStore
introduces modular, granular, scalable storage that eases the transition to NAS:

• Reducing operating costs and management overhead
• As storage infrastructures scale up and out to accommodate more virtual machines and growing business
requirements
• By smoothing hardware lifecycle financial shocks at deployment, upgrade, and replacement

Manageabilit y
Manageability
VirtualStore is integrated with VMware vCenter for end-to-end management of whole virtual machines, including storage,
from a single console. Virtual machine administrators can continue using their familiar vCenter tools, and won’t have to
learn additional management tools, shuttle between consoles, or rely on storage specialists for routine tasks. VirtualStore
enhancements to vCenter include:

• FileSnap snapshot capability, so administrators can create, store, and provision space-optimized boot VM boot
images from within vCenter
• Labeling of clone images and customization of their hosts and network interfaces to avoid conflicts, from the
same vCenter console

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• Integration VirtualStore and VMware View desktop management, extending VirtualStore management
capabilities to virtual desktop environments

Conclusion
This paper has focused on VirtualStore’s capability to provide cost-effective NFS storage to ESX host servers, but this is
only the beginning of the solution’s capabilities. Backed by Storage Foundation, which incorporates decades of experience
in the world’s most demanding storage environments, VirtualStore can:

• Provide NFS storage to other clients or directly to individual virtual machines
• Deliver advanced management, storage tiering, thin provisioning, and storage optimization services to meet the
most complex requirements
• Present storage to clients as Common Internet File System (CIFS) as an alternative to NFS, offering access to the
same data through both protocols

Symantec VirtualStore offers high-performance NAS storage at highly competitive price points, to extend the benefits of
virtualization wider and deeper throughout enterprise computing. VirtualStore offers High Availability and Business
Continuity/Disaster Recovery, thin provisioning, tiered storage, and desktop image deduplication and caching that bring
the power of comprehensive, mature storage management solutions to the virtual world.

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About Symantec
Symantec is a global leader in providing security,
storage, and systems management solutions to help
consumers and organizations secure and manage
their information-driven world. Our software and
services protect against more risks at more points,
more completely and efficiently, enabling
confidence wherever information is used or stored.
Headquartered in Mountain View, Calif., Symantec
has operations in 40 countries. More information is
available at www.symantec.com.

Symantec helps organizations secure and manage
For specific country offices Symantec World Headquarters their information-driven world with storage
management, email archiving, and backup and
and contact numbers, please 350 Ellis St. recovery solutions.

Copyright © 2011 Symantec Corporation. All rights
visit our website. Mountain View, CA 94043 USA reserved. Symantec and the Symantec Logo are
trademarks or registered trademarks of Symantec
+1 (650) 527 8000 Corporation or its affiliates in the U.S. and other
countries. Other names may be trademarks of their
respective owners.
1 (800) 721 3934 3/2011 21181908

www.symantec.com

Virtual store a nas software solution for v-mware environments

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