Calculating the return on investment (ROI) for block-based storage virtualization products can be tricky because it often boils down to an estimation of the soft costs associated with moving data and managing disk arrays.
The virtualization software creates an abstraction layer that lets IT shops treat disk arrays from different vendors as a single pool of storage. One of its main use cases is migrating data between storage systems, with the advantage of minimal if any disruption to the applications.
Virtualization products able to manage block-based storage from multiple vendors include DataCore Software Corp.’s SANsymphony-V, EMC Corp.’s Vplex, FalconStor Software Inc.’s Network Storage Server (NSS), Hitachi Data Systems (HDS) Corp.’s USP and VSP, IBM’s SAN Volume Controller (SVC) and SVC-based Storwize V7000 array, and NetApp Inc.’s V-Series.
“Most of the time, there’s not a really effective calculation of the ROI,” said Andrew Reichman, a principal analyst at Cambridge, Mass.-based Forrester Research Inc. “It’s hard to come up with a real number. Really, what you’re going to do is compare a few different scenarios of how you are going to accomplish this data migration.”
Russ Fellows, a senior partner at Boulder, Colo.-based Evaluator Group Inc., said the calculating ROI is oftentimes difficult because in many cases the existing storage systems remain. Also, the gains in IT administrative productivity can be tough to quantify, he noted.
Many IT shops don’t even bother with a formal ROI calculation. The city of Coquitlam, British Columbia, bought Hitachi’s USP VM -- the low-end version of the USP-V -- in 2008 after learning that its HDS Thunder 9570 arrays weren’t certified to work with a new version of VMware Inc.’s server virtualization.
Darren Browett, the Canadian city’s technical services manager, saw no reason to compute the potential ROI for the USP VM. “We needed storage. We had to have it, and it was the right technology fit for us with what we were trying to do with virtualized servers and building towards the future,” he said.
The USP VM helped to extend the life of the 9570s that it virtualized, and last year, when the time came to retire the Thunder arrays, the storage virtualization functionality enabled Coquitlam to move to new HDS Adaptable Modular Storage (AMS) 2100s with no appreciable downtime.
Cost savings with data migration
Storage virtualization will come in handy once again when Coquitlam moves to a new data center about five miles from the current site. Without the USP VM, the move would have required application outages over a weekend, when the city would have had to pay the staff overtime and potentially double the associated moving costs.
“It would have been expensive, and more so, it would have been an inconvenience to our staff,” some of whom need application access seven days a week, said Browett. He added that, with storage virtualization, the IT staff would be able to execute the move in the middle of a weekday with no downtime. “It’s a simple matter of clicking on that LUN and moving it [to] a target array in the new data center,” he said.
J. Craig Venter Institute (JCVI) purchased NetApp’s V3070 storage virtualization gateway to complement the EMC disk arrays it inherited in a late-2006 merger. The Rockville, Md.-based genomic research organization presented the EMC block storage through the V3070 because it wanted to use file-level protocols through NetApp’s Write Anywhere File Layout (WAFL) file system.
“Without it, these [EMC] arrays would have just sat there collecting dust,” said Eddy Navarro, senior manager of IT at JCVI. “At the time that we installed the V-Series, they hadn’t come close to full depreciation yet, so the remaining value on those arrays definitely factored into the ROI.”
Navarro said he didn’t calculate “a hard and fast number.” He weighed the price of the V-Series controller versus the cost to buy a new NetApp FAS controller with an equivalent amount of storage.
“It was a no-brainer,” said Navarro. “We were already a NetApp customer, and that was it.”
Now that JVCI has a V-Series at both its Rockville and San Diego locations, Navarro is looking into the prospect of doing replication between the two sites. He said it’s nice to know that he has the option to add third-party storage behind either V-Series. NetApp has qualified V-Series to front arrays from EMC, HP (including 3PAR), HDS, IBM and Fujitsu and made its deduplication technology available for EMC, HP and HDS storage.
“Even if I buy [an EMC] VNX, I could still present some of that storage back to the V-Series for project area NAS space if I need to,” Navarro said. “I’m not locked in to just having to buy NetApp disk shelves if I can’t use them.”
Heterogeneous replication for disaster recovery is one of the main ROI plays for storage virtualization, according to Howard Marks, chief scientist at Deep Storage LLC, an independent test lab and analyst firm in Hoboken, N.J. With a storage virtualization engine at the primary data center and DR site, users can replicate data without having to run an array from the same family at each location, he said.
Marks said he’s seen several organizations use older gear at their DR sites. For example, after buying a new EMC Vmax to replace a Symmetrix, an organization could move the old Symmetrix to the DR site instead of giving it back to EMC for a small credit or buyback. That would eliminate the need to buy two Vmax arrays.
Replication was a significant factor in the overall ROI calculation when CommuniCare Health Services undertook a major IT project to virtualize its servers and implement its first shared storage system, according to Jerry Williams, a SQL Server database administrator and developer at the Cincinnati-based health care management company.
Williams said CommuniCare chose FalconStor’s NSS over disk arrays from Dell Inc.’s EqualLogic, Hewlett Packard Co.’s LeftHand and NetApp because it offered the best cost structure to meet the company’s needs. Another big attraction was FalconStor’s ability to front any vendor’s storage arrays, he said. That opens the possibility to use cheaper storage for DR.
“Storage virtualization is a product category that requires an open mind,” Marks said. “A lot of the benefit comes from heterogeneity. That means you have to be open to heterogeneity, and a lot of customers aren’t. If it doesn’t say EMC or HDS or HP on it, they don’t want to buy it.”
Improved resource utilization
Another key ROI source for storage virtualization is improved resource utilization through the consolidation of old and new arrays. Putting disparate storage under common management also can help to reduce the training costs as well as staff time needed to provision and administer the different systems.
“The whole point of what we’re trying to do is to manage more [storage] more efficiently,” said Valdis Filks, a research director of IT infrastructures at Stamford, Conn.-based Gartner Inc. “And you can achieve probably 90% of all virtualization benefits by just consolidating into fewer larger storage arrays.”
Filks said the ROI is highest for IT shops with lots of old, heterogeneous storage arrays that are labor-intensive to manage, although storage administrators may still need to use the device’s native tools for procedures such as changing the RAID size, block sizes or caching parameters.
While the ROI potential may be greatest in a heterogeneous environment, many IT shops use storage virtualization in a single-vendor setting. One of the most popular products, SVC, caught on when IBM promoted the technology to upgrade its own arrays.
For instance, Spectrum Health System in Grand Rapids, Mich., updated its aging IBM Shark SAN infrastructure to IBM’s DS8300 several years ago while moving to a new data center. Purchasing IBM’s SVC appliance allowed the IT team to migrate data with minimal disruption to applications that Spectrum’s hospitals use around the clock.
But, once an IT shop puts all of its storage under the management of the virtualization layer, it may have a hard time backing out. Because software virtualization tends to lock in a customer with a specific vendor, Forrester’s Reichman advises IT shops to consider their comfort level with a vendor and the product’s management stack and features more so than the ROI they might realize.
“Storage virtualization can deliver a tangible ROI, but I think the fit with everything is a bigger concern,” Reichman said. “‘Is this the product that you want to use long-term?’ is a more important question than ‘Are you going to save 3% in acquisition costs this year?’ ”