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One of the bonuses of buying a storage virtualization product is that it lets storage managers extend the life of older arrays. Cranky, old systems suddenly get brand-new features such as point-in-time copies, dynamic LUN expansion and additional cache. But there are some traps users should be aware of when weighing the benefits of virtualizing older systems vs. purchasing newer ones. For example, hardware maintenance and environmental costs can negate the savings from virtualization.
Hitachi Data Systems (HDS) found this out recently with a customer in Korea, and HDS storage consultant and solution architect David Merrill blogged about the findings. (HDS has since removed his posting and has declined to comment on the topic any further. A cached copy of the story is still available on the SearchStorage.com blog.) Merrill noted that for this particular customer's environment, which contained fewer than 18TB of storage data, the total cost of virtualizing older storage using a Hewlett-Packard (HP) XP Series virtualization system (the HP XP is a rebranded TagmaStore system) was more than the cost of buying new storage.
"Users should perform a careful total cost of ownership [TCO] analysis with this technology, as the price tag of these products can often be greater than the savings they afford," says Greg Schulz, founder and senior analyst at the StorageIO Group, Stillwater, MN.
Several conditions impacted the storage TCO for this Korean company,
Not everyone is struggling to see the cost benefits of storage virtualization. For QBE Regional Insurance in Sun Prairie, WI, virtualizing old storage arrays reduced the company's total storage costs significantly and brought capacity utilization up by more than 10%, according to Loren Eslinger, senior systems engineer at QBE. The company virtualized two old HDS Thunder 9570V storage systems with IBM's SAN Volume Controller (SVC), a fabric-based virtualization product, and added an array from IBM.
Eslinger agrees that there's a point at which virtualization becomes cost-effective. QBE Regional Insurance manages 50TB of storage data and found that virtualization costs decreased as the quantity of virtualized terabytes increased. "Licenses are based on terabytes of usable storage, meaning that smaller environments may not see a significant savings," says Eslinger.
This was first published in September 2007