Storage Virtualization Guide

Next reports Reports.InformationWeek.com May 2012 $99 Storage Virtualization Guide

Virtualized pools of storage can increase disk utilization, give storage administrators more flexibility, and improve disaster recovery and business continuity. From thin provisioning to replication to federation, virtualization options can make your storage more supple and responsive—and free you from vendor lock-in. Our guide tells you how.

By Howard Marks

Presented with

Report ID: S4500512 Previous Next

reports Storage Virtualization Guide S

3 Author’s Bio ABOUT US 4 Executive Summary T 5 Storage Gets Virtual InformationWeek Reports’ analysts arm 5 Figure 1: Use of Storage Virtualization business technology decision-makers 6 Figure 2: Storage Technologies in Use with real-world perspective based on 6 Virtual Storage Basics qualitative and quantitative research, N 8 Figure 3: Planned Projects business and technology assessment 9 Figure 4: Extent of Storage Technology Use and planning tools, and adoption best 10 Figure 5: Storage Consolidation Plans practices gleaned from experience. To E 11 Figure 6: Leaders in Storage Virtualization contact us, write to managing director 12 Figure 7: Storage Federation With Virtual Art Wittmann at [email protected],

T Storage Appliances content director Lorna Garey at 14 Hosts and Appliances [email protected], editor-at-large Andrew 14 Virtual Storage Appliances Conry-Murray at [email protected], and 15 SANs and Arrays research managing editor Heather Vallis at

N 17 Related Reports [email protected]. Find all of our reports at reports.informationweek.com. TABLE OF O C reports.informationweek.com April 2012 2 Previous Next

Table of Contents reports Storage Virtualization Guide

Howard Marks is founder and chief scientist at DeepStorage.net, a storage and networking consultancy based in Hoboken, N.J. In more than 25 years of consult - ing, Marks has designed and implemented storage systems, networks, manage - Howard Marks ment systems and Internet strategies at organizations including American Express, InformationWeek Reports JPMorgan, Borden Foods, U.S. Tobacco, BBDO Worldwide, Foxwoods Resort Casino and the State University of New York at Purchase. He has been a frequent contributor to Network Computing and InformationWeek since 1999 and a speaker at industry conferences including Comnet, PC Expo, Interop and Microsoft’s TechEd since 1990. He is the author of Networking Windows and co-author of Windows NT Unleashed (Sams).

Want More? Never Miss a Report!

FoFollollow w FoFollollow w

Table of Contents reports Storage Virtualization Guide

Storage virtualization techniques such as volume management, thin provisioning and federation can help organizations increase their utilization of storage space, ease data Y migration exercises, and improve disaster recovery and business continuity measures. IT leaders have numerous options when it comes to taking advantage of storage virtualization. For instance, most modern disk arrays include some virtualization capabilities, such as

R volume management and thin provisioning. Storage virtualization can also give companies more flexibility when it comes to the products they buy. Consider a typical replication environment, in which data from a disk array in one data center is written to a disk array in a second data center; both arrays must A be the same product from the same vendor. However, third-party storage virtualization appliances, which sit in-line in front of the arrays, let companies mix and match their storage systems and protocols while still getting the data protection that comes with replication. Storage virtualization appliances can also help enable federation, a more advanced form of

M replication that provides both data protection and the ability for a company to recover quickly from a complete data center failure. This report looks at the storage virtualization options available to companies and high - lights the pros and cons of each. It also examines the various places within the IT infrastruc - ture where storage virtualization can take place, including servers and disk arrays, and via M physical and virtual appliances.

EXECUTIVE U S reports.informationweek.com April 2012 4 Previous Next

Table of Contents reports Storage Virtualization Guide

Storage Gets Virtual

The rapid adoption of server virtualization, and the growing acceptance of desktop virtu - Figure 1 alization via VDI, has reawakened interest in vir - Use of Storage Virtualization tualization in the storage arena. As IT realizes Do you use storage virtualization? the value it gains from the efficiency and flexi - 2012 2011 bility of compute virtualization, it has started Yes, all of our disk storage is in a single virtual pool of storage asking why its storage resources can’t be as 7% 5% flexible. In fact, 31% of storage professionals Yes, some of our storage systems are in a virtual pool use some kind of storage virtualization, accord - 31% ing to the 2012 InformationWeek State of Stor - 31% age Survey (Figure 1). No, but we are planning to implement it in the next 12 months 8% If we define storage virtualization broadly as 12% any technology that presents storage in a new No, but we are looking into it configuration, we’ve all been virtualizing stor - 30% age for many years; even DOS had enough vol - 29% ume management smarts to divide a large disk No, we’re not interested 15% into multiple logical volumes. Today, basic vol - 15% ume management features are so common Don’t know that we no longer even think of slicing a disk 9% into multiple volumes, or combining multiple 8% disks into a RAIDset, as storage virtualization. Base: 313 respondents in January 2012 and 377 in November 2010 R4190212/17 Data: InformationWeek State of Storage Survey of business technology professionals Similarly, many storage virtualization features that were once only available in a dedicated reports.informationweek.com April 2012 5 Previous Next

Table of Contents reports Storage Virtualization Guide

storage virtualization product are available on ment and snapshots, though vendors may ple, if you have 2 EMC Clariion arrays, you can’t most modern disk arrays. For instance, disk ar - charge license fees to enable some or all of create a volume that spans both arrays with - rays now include virtualization capabilities those features. In addition, the scope of the out having volume management external to such as thin provisioning, volume manage - features is limited to a single array. For exam - both the arrays. Figure 2 Other types of storage virtualization, such as Storage Technologies in Use heterogeneous replication and federation, are Which of the following storage technologies and features are in use at your organization? more commonly accomplished via the use of storage virtualization appliances. These de - 2012 2011 vices sit in-line in front of arrays and create a e % g a 7 r 6

o common interface for hosts, allowing admin - % t % 3 s

2 ) 6 6 1 istrators to mix and match the protocols and

r % % e 7 i % % 6 T 5 5 5 arrays that sit behind the appliances. We’ll ( 5

% 5 5 y % 2 r 1 a 5 look at several types of storage virtualization, 5 % m i 7 r % 4 p 5 and drill into the pros and cons of each ap - 4 n o

) % %

n proach. We’ll also look at the various places 8 8 o s i r 3 3 s y e % s a % % v within the storage infrastructure where virtu - 4 r e % r ) 3 3 r r 3 e 2 a D p 3 3

s I

% 3 k % % % m A n

9 alization can take place, including on servers, s % i i o 8 8 8 2 M h 7 c p d )

2 2 2 (

s r u 2 i s n % L k o s in disk arrays, and through both physical and

k w o T t c 3

s e ) ) i o a V % % 2 s s p ( d b h

n 0 0

u D D s s

o virtual appliances. e e 2 2 S S i d p l e i t p n S S e a g d r ( ( a i a o n

n d

g n n i a t z s s ( % i f o s o t r i -

i r i l k k i o 3 a b o s

n t % e d s s a i c n t s i i i 1 y l a o i 1 e -

u t i l o e z d d

a s t i

t k e i r 1 r p % l r n d s a s

c Virtual Storage Basics e e r n p i p i i u a 9 e t t o b u a v o a v i t d

- d a a i u m t t d - o

a t t t e t e e e l r o a e o r s s v p g g i r d c c

a Storage virtualization provides a consistent t - - i p m

y - a a s v l u d d

o a a a r r r s n i i k t t t t t p A A c i l l e s o o r a l / / a a a i u e i o o t t n h i interface for management functions and M S A T S F D V S D D E S D R N N

Note: Percentages reflect a response of “use widely” or “limited production use” R4190212/9 hosts across multiple storage systems, as well Base: 313 respondents in January 2012 and 377 in November 2010 as a group of storage management features. Data: InformationWeek State of Storage Survey of business technology professionals reports.informationweek.com April 2012 6 R Previous Next

Table of Contents reports Storage Virtualization Guide

These include volume management, thin pro - across the disks (for example, RAID 0 is strip - space, administrators create volumes big visioning, snapshots, heterogeneous replica - ing without parity and RAID 5 is striping with enough to hold not just the data that will be tion, live migration and, most recently, storage parity). Concatenation fills the first disk, then placed on that volume today, but enough to acceleration. Note that some vendors use the writes to the second disk, and so on. hold the data that volume is expected to hold term “storage hypervisor” to describe their Volume management features also support in the future, plus a “safety factor” of 10% to storage virtualization products. Technically mirroring, occasionally with multiple replicas, 50%. While this practice helps ensure that the they aren’t hypervisors, but the term is used which provides disk system fault tolerance server will have sufficient storage, it reduces a to evoke the notion of abstracting the con - comparable to synchronously mirroring be - company’s overall utilization of disk space, be - nection between the physical disk and the tween two disk arrays, but with better recov - cause some percentage of the storage allo - hosts accessing that disk. ery. In most replication environments, the cated to the server goes unused. > Volume Management data will replicate to the second array. But if Many organizations further reduce their uti - Volume management features usually in - the primary array fails, the host will lose access lization through policies such as allocating ar - clude building a volume by striping across to the data and the application will have to be ray volumes to servers in standard sizes. If an How To Write an Effective multiple LUNs with or without parity. Volume connected to the secondary array and Oracle DBA comes to the storage team and SAN RFI management frees host operating systems restarted. Mirrored systems will continue run - says he needs 480 GB of space, the storage ad - Storage and networking are and applications from the volume manage - ning with a failed logical disk. Disk system fed - ministrator allocates 750 GB because there ground zero for the next ment limitations of their storage systems. If eration aims to provide automatic failover by wouldn’t be enough headroom in a 500-GB enterprise data center upgrade wave. This time, architecture your disk array can only extend a volume to automatically activating paths to the second - LUN and 750 GB is the next standard size. As designs will be based on free space in the same RAIDset, but you need ary array. a result, most organizations only use (that is, virtualization and private clouds, not discrete servers and local more space for your Exchange server than is > Thin Provisioning actually write data to) 30% to 50% of the disk disks. Translation: Plenty of IT free in that RAIDset, a virtualization platform On standard storage systems, a logical vol - space they allocate to servers. Enterprises rec - teams are in the market for SANs. Here’s how to make vendors with volume management could concatenate ume consumes a constant amount of space ognize that they aren’t getting full utilization work for your business. or stripe the existing volume with a new vol - from the time it’s created, or provisioned, until of their disk space. Consider that the top two ume from another RAIDset or even a different it’s discarded (if ever). Because servers be - projects planned for 2012 are improved allo - Download disk array. Striping spreads the data evenly come unhappy when they run out of disk cation of storage and the reclamation of un - reports.informationweek.com April 2012 7 Previous Next

Table of Contents reports Storage Virtualization Guide

used storage, according to our storage survey space. That’s because thin provisioned systems a few megabytes of disk space, even though (Figure 3). don’t allocate disk space to volumes until the server connected to it sees a 750-GB logical Thin provisioning is one way to improve allo - they’re actually written to. An empty 750-GB disk. Many organizations find that thin provi - cation and reduce the amount of unused disk LUN on a thin provisioned system takes up just sioning allows them to allocate volumes be - Figure 3 Planned Projects What key projects and processes do you plan to implement over the next 12 months?

2012 2011 r e h t % o 1 n 5 % a

8 o t 4

a t e a g d a

% r f % m 2 o o

e t 1 4 s t s %

4 s e f 9 y p % % % o s 3

y % r 7 7 7 t t

e 6 3 3 3 n i t t 3 e n

% e e m 3 r n e 3 e o f g

f i a s m n d n k

o % a r a f l r e 7 f o o

p c

m %

s i 2

a e w t s y v 5 e t t t r u r n c 2 l a s e e r e e a d e e n v s

u n

v f g u m o

o o e % % a s c

i a o e q s g

% % % % g 0 0 r t s r s e e e e i n % n a r 9 9 9 9 a e o a r 2 2 r i g

u t % % z o 8 r n 1 1 1 1 a n i i y e s e o i q % l r

7 7 e t r 1 t n i s g f g t e % o 6 a s t e 1 1 r a

s u a n o a t r

% s l 5

v 1 u r r s a d b

o N e

g A

4 p o n 1 i o s i o

c e n i % c t L A d t e t 1 o y s a n g i s % % S s S d a e 2 m

h t

i a a s z t r 1 1 a 1 i

d i a a a p r c a e

l l u t o 1 1 c

g a o u h o g g g a a p n % % t o t e t n k p

n n n d u i s u 9 9 c

i i i m a t g g d t t t a c a r g a g g o

n i n r n n n n b c i n i n n

d d v i i i t a o

e e e d r g g e e t t g a e s s n v v r m o m m m n n

i g r i i t r o e o o m e e e i % % d t t a a e l l l r r v e o l p r n e e u 2 2 d p p p p p t s c A n h o e e o o / n t u e e l t o m m m m m O R M U M C I I A S C I M I R I N

Note: Multiple responses allowed R4190212/16 Base: 313 respondents in January 2012 and 377 in November 2010 Data: InformationWeek State of Storage Survey of business technology professionals reports.informationweek.com April 2012 8 R Previous Next

Table of Contents reports Storage Virtualization Guide

yond the actual disk space they’ve purchased. Figure 4 The downside to thin provisioning is that if Extent of Storage Technology Use those volumes grow to the point that the sys- To what degree are the following storage technologies and features in use at your organization?

tem runs short of disk space, the storage ad- Won’t use No plans for immediate use Under evaluation/pilot Limited production use Use widely ministrators may not have a lot of notice to 4% 5% 5%

deal with this storage equivalent of a margin 9% 13% 7% 16% 16% 20%

call. While this may result in panic on a thinly 21% 22% 22% 23% 15% 18% 11% 30%

provisioned array, as administrators race to 12% 41% 43% 18% add capacity to that array, users with external 12% 17% 13% 16%

storage virtualization systems can pool stor- 21% 23% 22% 24%

age from multiple back-end arrays or migrate 30% 35%

volumes to arrays with additional space trans- 26% parently to the hosts and users. 57% 19% > Snapshots 26% Storage snapshots provide a point-in-time 46% 38% 11% 41% 16% 44% view to the contents of a file system or storage 40% 40% 20% 35% 21% volume. Snapshots are used for the rapid re- 30% 24% 23% 24% 21% 15% 15% 12% covery of data sets that may be damaged or 22% 19% 21% 20%

corrupted, as well as to create space-efficient 16% 14% 20% 17% 15% 13% 13% 13% 11% 11% 9% 8% 8% 8% 7% 3% 4%

copies of data sets for development, test and backup Disk-to-disk-to-tape Replication snapshots Storage-based deduplication Data virtualizationStorage compression Data Virtual tape libraries (VTLs) Encryption provisioning Thin on primary reduction (dedupe or compression) Data (Tier 1) storage virtualizationFile tiering Automated disks (SSDs) within serversSolid-state disks (SSDs) on disk array Solid-state of idle disks (MAID) array Massive

related uses. Most importantly, when coordi- Data: InformationWeek 2012 State of Storage Survey of 313 business technology professionals, January 2012 R4190212/8 nated with applications via scripts or Windows VSS (Volume Shadow copy Service), snapshots ondaryR storage for safe keeping. on-write technique. When an application provide application-consistent data sets that Most storage systems and virtualization writes data to a given location on a snap- backup applications can then copy off to sec- platforms create snapshots using the copy- shot-protected volume, the storage system reports.informationweek.com April 2012 9 Previous Next

Table of Contents reports Storage Virtualization Guide

Figure 5 copies the contents of that location to the snapshot storage location. When a snapshot Storage Consolidation Plans Have you consolidated, or are you planning to consolidate, storage into fewer, centrally managed systems? is mounted, the system reads from the snap - shot location for blocks that have changed since the snapshot was taken, and from the Yes, we’ve already consolidated Yes, we’re planning to do primary location for data blocks that have re - 25% so in the next 12 months 18% mained the same. A copy-on-write snapshot system has to perform three I/O operations when data is Don’t know 9% written to a volume: It has to read the current data, write it to the snapshot store and write 31% the new data to the 17% Yes, but there’s no specific timeframe block. Another option is No Thin provisioning is one way to redirect-on-write. Sys - improve allocation and reduce the tems that use the redi - Data: InformationWeek 2012 State of Storage Survey of 313 business technology professionals, January 2012 R4190212/25 amount of unused disk space. rect-on-write system are more efficient be - quentially. Organizations have to decide ever, it is limited because disk arrays can only cause rather than copying the existing data to wRhether to prioritize efficiency or thro ughput replicate data to disk arrays from the same a snapshot, they write the new data to an in choosing which technique to use. product line. Even loyal BIGco customers soon empty storage location using pointers to > Heterogeneous Replication discover you can’t replicate data from a BIGco manage the current state of the volume. While Array-based replication, in which data is Midsize Array in the St. Louis office to the BIGco redirect-on-write systems don’t suffer a write copied from one array to a second array in a Huge Array at headquarters or vice versa. performance penalty for their snapshots, they different data center or disaster recovery site, Storage virtualization products allow organ - can have somewhat lower throughput for se - is a common part of the business continuity izations to use different disk arrays in their pri - quential reads, as data may not be stored se - and disaster recovery (BC/DR) process. How - mary and secondary sites. This allows an or - reports.informationweek.com April 2012 10 Previous Next

Table of Contents reports Storage Virtualization Guide

ganization to use a less-powerful array, like cant savings. All it has to do is install storage Each appliance will write its data to a local the last generation of its primary storage ar - virtualization appliances in both locations and storage array. Those two arrays need not ray, at the DR site, which can result in signifi - replicate between them. even run the same SAN protocol, let alone be Figure 6 Leaders in Storage Virtualization Which of the following vendors do you consider leaders in storage virtualization?

2012 2011 % 0 % 5 8 Like This Report? 4 Rate It! % 7 %

Something we could do 3 5 better? Let us know. 3 % % 0 0 3 3 % % Rate 6 5 2 2 % 1 2 % s 6 k 1 r o % % w % 2 2 t 1 t 1 1 e ) c 1 n i p N

e s g l p i % d l o r A e 8 n L a t r l w l % % p a c e a o o o % % % 6 6 e e H t R N u m S r n % % t t 5 5 5 ( S / p h A t

f o q k o % % % % 4 4 n

c n d e e p P r e o e E C C t % i l l a 3 3 3 3 * ’ e r / / o L 3 e A a n c c l l a % % % % % t C 2 c / / a t n l l t A A A A A A A r h a m l a a M o 1 1 1 1 1 / / / / / / / e P P P t o a e e n r r i x M y o a B D O O D C E X F O H S O D H D I H N E N N N N N N N

*Change in vendor name from 2011 R4190212/30 Note: Three responses allowed Base: 313 respondents in January 2012 and 377 in November 2010 Data: InformationWeek State of Storage Survey of business technology professionals reports.informationweek.com April 2012 11 R Previous Next

Table of Contents reports Storage Virtualization Guide

Figure 7 from the same vendor. The replication goes Storage Federation With Virtual Storage Appliances appliance to appliance, and then the appli - Servers Servers ances write to their local arrays, so the fact that there are different arrays at both ends doesn’t effect reliability. However, you’ll need a pair of appliances at each location (be - cause one could fail), so this solution comes with some costs. Virtual Storage Virtual Storage Replication Appliance > Storage Migration Appliance Even with the latest generation of storage arrays that have a full set of internal virtualiza - tion features, migrating data from one array to another is a major undertaking. Adminis - trators have to schedule downtime to shut Storage Array Storage Array down the applications on the source system and transfer the data before the application can be restarted on the new array, which could take hours. A virtualization system can migrate data from one back-end array to another in the background, prioritizing host Like This Report? access over data movement. Volume A Volume A Share it! Many organizations bring in storage virtual - Primary Data Center Secondary Data Center ization products specifically to ease migra - Federation uses virtual storage appliances to replicate data simultaneously among disk arrays in two or more data Like TTweetweet centers. In this configuration, disk storage (Volume A) is presented to servers in both the primary and secondary data tions. While some downtime is usually centers, even though the master copy is in the primary data center. If a disk array in either data center fails, the servers Share transparently fail over to the other array. If an entire data center fails, applications can be restarted quickly in the other required to mount LUNs through the virtual - data center because the storage volume doesn’t need to be reconfigured and mounted. reports.informationweek.com April 2012 12 Previous Next

Table of Contents reports Storage Virtualization Guide

ization system, the application can be up and age virtualization products have used RAM to The hosts in each data center access the running again in a few minutes instead of provide an additional layer of caching, the im - volume through data paths to their local ar - down for hours. pact on performance was limited, as a few gi - ray, which may run through a local virtualiza - FalconStor’s NSS goes a step further by gabytes of RAM just wasn’t enough to have a tion appliance. The servers in the other data passing the identity of the LUN from the back- big impact on application performance. center access the data through their local end storage array through the virtualization Just as storage array vendors have been storage. The federation system in both data appliance. An administrator can mount the adding flash memory to their controllers, vir - centers replicates write data to each other LUN on the appliance and then use the host’s tualization vendors have been figuring out and each writes data to the storage arrays in multipath software, how to include flash in theirs. Some, like Fal - their local data center, keeping the data on With a federated system an adding paths through conStor NSS and NexentaStor, can use flash in both arrays synchronized (Figure 7). organization can build stretched the appliance and then the virtualization appliance as a cache, while While conventional replication provides clusters with members in different removing the paths others, like IBM’s SVC (SAN Volume Controller) data protection, federation goes two steps that ran directly to the and DataCore’s SANsymphony, will combine further, allowing access to the volume at data centers, turning disaster array. Because paths SSDs and traditional disks to create storages both the primary and secondary systems recovery into disaster avoidance. can be dynamically pool with automated sub-LUN tiering and maintaining the same volume identity added and removed, no between the SSD and disk. across multiple systems. An array failure in actual downtime is required. Several profes - > Storage Federation one location will cause a transparent failover sional services organizations, including Storage federation is the latest tool in the to the array in another location. In a federa - Fujitsu’s, use NSS as a temporary tool for their storage architect’s toolkit. Storage federation tion system, virtual machines and the appli - migration services. is offered by IBM’s SVC and is EMC’s VPLEX’s cations that run on top of them can be > Storage Acceleration primary claim to fame. Storage federation ex - moved from site to site. Recently storage virtualization vendors, like tends the data protection aspect of data repli - In the event of a data center failure, appli - everyone else in the storage industry, have cation to turn a set of independent disk arrays cations can be restarted faster because LUNs started adding SSDs to their products to accel - into a single federated storage system across don’t need to be reconfigured and mounted. erate storage access. While most in-band stor - multiple data centers. With a federated system, an organization can reports.informationweek.com April 2012 13 Previous Next

Table of Contents reports Storage Virtualization Guide

build stretched clusters with members in tipath management, SSD acceleration and SANsymphony-V is a software product that different data centers, turning disaster recov - just about any other storage management runs on Windows Server. ery into disaster avoidance. Of course, all of feature you can think of. Installing an in-band virtualization appli - these benefits come at a price. You’ll need As VMware has become the driving force for ance usually requires some downtime as ex - two appliances at each site and significant many organizations’ storage decisions, tradi - isting LUNs are assigned to the appliance and amounts of bandwidth between sites to tional volume manager-driven storage virtu - host access to the volumes is remapped to make federation work. alization has become less attractive to many use the appliance. However, if properly man - users. While vSphere doesn’t include a volume aged, this downtime can be limited to a few Hosts and Appliances manager per se, many of vSphere’s storage minutes per host. Because data access passes The earliest storage vitalization product was features, such as thin provisioning, solve the through the appliance, most organizations the volume manager, which allowed a user to same problems as more traditional storage will deploy appliances in redundant pairs or slice and dice a hard drive into multiple vol - virtualization platforms. For example, Storage clusters so that the failure of one appliance umes. The lowly volume manager grew over vMotion and VMware SRM’s replication ad - won’t cut off access to the storage system. time to include functions like RAID, thin pro - dress the need for transparent migration and visioning and snapshots. Most operating sys - heterogeneous replication for hypervisor im - Virtual Storage Appliances tems, from AIX to Windows, include volume ages, applications and data. As more and more servers are virtualized, managers that can create RAIDsets and divide Dedicated storage appliances represent the storage vendors have developed software them into volumes. A volume manager run - most common platform for external storage that performs some of the same functions as ning on a server can manage disks directly at - virtualization. Storage appliances sit in the a physical appliance, but is instead delivered tached to, or internal to, the server, as well as SAN data path between host servers and stor - as a virtual machine that runs on a hypervi - manage logical volumes presented by a stor - age arrays. Appliances such as EMC’s VPLEX, sor. This software is called a virtual storage age area network. IBM’s SVC and FalconStor’s NSS combine stor - appliance. Because many of the most inter - Symantec’s Storage Foundation, which grew age virtualization software with industry- esting hypervisor features, such as live mi - out of the widely used Veritas Volume Man - standard x86 servers. Others, like NetApp’s V- gration and high availability, require some ager, adds snapshots, thin provisioning, mul - Series, use custom hardware. DataCore’s sort of shared storage, VSAs make these fea - reports.informationweek.com April 2012 14 Previous Next

Table of Contents reports Storage Virtualization Guide

tures available to branch offices and SMB and take advantage of the management solutions were never successful in the market - server rooms that can’t justify the cost and tools provided by vSphere. place and are close to extinction. complexity of a traditional SAN. Some storage vendors, including EMC and You can also virtualize storage in the array. When you install a VSA on a host, you NetApp, have limited-use or limited-distribu - For example, Hitachi Data Systems’ VSP high- assign it disks, typically local disks on the tion VSAs that emulate their hardware storage end disk arrays can, in addition to managing physical server. The VSA then offers those systems. While these VSAs aren’t designed for their internal disks, add volumes from HDS or disks to the hypervisor and/or other servers production use, they can come in handy for other vendors’ external disk arrays to their via storage protocols such as iSCSI or NFS. training and test environments. management pool by inserting the VSP in These smaller hypervisor environments can the data path between servers and the connect disk drives to the internal RAID con - SANs and Arrays external arrays they’re managing. Once ex - troller in their hypervisor host and have a A few years ago several vendors, including ternal volumes are virtualized into VSP vol - VSA running in that Brocade and Cisco, proposed using the Fibre umes, they gain the full set of VSP features, Array-based virtualization can host share the disk out Channel switch as a virtualization platform. including thin provisioning, replication, au - via iSCSI or NFS. They built x86 processors into their switches tomated tiering at the sub-LUN level and au - bring the advantages of storage There’s a wide range and invited ISVs to port their software for tomated data migration. IBM’s Storewize virtualization to the data center of functionality in the replication, volume management and the v7000 midrange arrays can also virtualize ex - without the complication of VSAs available today. like to the switch platform. Some implemen - ternal storage by leveraging the fact that the additional appliances. Some, like StarWind, tations ran out of band, with the virtualiza - v7000 is based on the SVC code base. Openfiler and Nexen - tion platform providing the control plane Array-based virtualization can bring the taStor, are virtual server versions of the ven - while data passed through the intelligent advantages of storage virtualization to the dor’s software that was originally designed SAN switch without passing through the data center without the complication of ad - to turn a physical server into iSCSI targets or server-based virtualization appliance. ditional appliances. The problem is if you’re unified storage system. Others, like Stor - While a few such applications, like the write not already a Hitachi VSP or IBM Storewize Magic and VMware VSA, were designed splitter for EMC’s RecoverPoint replication V7000 customer, you have to add a new array specifically for the hypervisor environment product, are still available, these switch-based to your current storage system to get it. This reports.informationweek.com April 2012 15 Previous Next

Table of Contents reports Storage Virtualization Guide

could be a good idea if you also need addi - tional storage, but it’s an expensive solution if you’re just looking for virtualization. Sim - plifying migration is one of the biggest rea - sons to implement storage virtualization, so the appliance approach, which can be used with any storage system, is probably more appropriate for most users. Storage virtualization, whether it’s imple - mented as a dedicated appliance or as a fea - ture of a storage array or hypervisor, can make both you and your storage system more effi - cient. Transparent migration and a consistent user interface across multiple storage systems make your life easier, while thin provisioning and snapshots can boost your storage utiliza - tion, reducing the amount of storage you keep empty “just in case.”

reports.informationweek.com April 2012 16 Previous

Table of Contents reports Storage Virtualization Guide

Want More Like This? InformationWeek creates more than 150 reports like this each year, and they’re all free to registered users . We’ll help you sort through vendor claims, justify IT projects and implement E new systems by providing analysis and advice from IT professionals. Right now on our site you’ll find:

R State of Storage 2012: Data center storage shows all the signs of a maturing discipline: IT professionals are more concerned about data reliability, security and performance versus LIKE THIS just keeping up with capacity demands. Although centralization has been the mantra for several years, distributed, scale-out systems are challenging the hegemony of big storage O iron. And with solid state reaching new levels of affordability, it’s rapidly displacing mechanical disk for many Tier 1 applications. In short, it’s an interesting time to be in the storage business.

Buyer’s Guide: Cloud Storage, Backup and Synchronization: The cloud is displacing local M physical storage for applications as diverse as file sharing, backup and cross-device data synchronization. Both business users and IT are adopting cloud services because of their convenience and low costs. We examine the market landscape and present detailed features Newsletter and pricing from 14 providers, including Carbonite, Dropbox and Nirvanix. Want to stay current on all new InformationWeek Reports ? Cloud Storage Buyer’s Guide Vendor Chart: This companion to our Buyer’s Guide: Subscribe to our weekly newsletter and never miss Cloud Storage, Backup and Synchronization contains complete responses from the a beat. 14 participating vendors.

Subscribe PLUS: Find signature reports, such as the InformationWeek Salary Survey, InformationWeek 500 and the annual State of Security report; full issues; and much more. reports.informationweek.com April 2012 17