SSymantec VirtualStoreymantec VirtualStore

A NAS Software Solution forVMware Environments

White Paper: Storage Management

SSymantec VirtualStoreymantec VirtualStore

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 SummaryVirtualization 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.

IntroductionVirtualization—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 NASVirtualization 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

Symantec VirtualStoreA NAS Software Solution for VMware Environments

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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 bottleneckBut 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 NASAn 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 VirtualStoreSymantec 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

Symantec VirtualStoreA NAS Software Solution for VMware Environments

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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 economicsPrice 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-

Symantec VirtualStoreA NAS Software Solution for VMware Environments

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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 advantagesSymantec VirtualStore unbundled high-performance NAS storage outperforms appliance-based NAS in virtualized

environments in a broad spectrum of use cases.

Adding capacitAdding capacityy

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

Symantec VirtualStoreA NAS Software Solution for VMware Environments

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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 resourcesUpgrading 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 throughputIncreasing 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).

OpOptimizing desktop delivertimizing desktop deliveryy

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 AHigh Avvailabilitailabilityy

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 continuitBusiness continuity and disasy and disaster recoverter recoveryy

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.

SnapSnapshoshotsts

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.

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RemoRemote and branch officeste and branch offices

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 FoundationVirtualStore 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

EEconomconomy and perfy and performanceormance

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

ManageabilitManageabilityy

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

ConclusionThis 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.

Symantec VirtualStoreA NAS Software Solution for VMware Environments

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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.

For specific country offices

and contact numbers, please

visit our website.

Symantec World Headquarters

350 Ellis St.

Mountain View, CA 94043 USA

+1 (650) 527 8000

1 (800) 721 3934

www.symantec.com

Symantec helps organizations secure and managetheir information-driven world with storagemanagement, email archiving, and backup andrecovery solutions.

Copyright © 2011 Symantec Corporation. All rightsreserved. Symantec and the Symantec Logo aretrademarks or registered trademarks of SymantecCorporation or its affiliates in the U.S. and othercountries. Other names may be trademarks of theirrespective owners.3/2011 21181908