4 Storage Virtualization Products That Offer Thin Provisioning

However, solution providers and their customers have found that storage virtualization, and thin provisioning technology in particular, is the ideal way to maintain storage management flexibility and costs.

In traditional storage provisioning, an application is allocated a fixed amount of storage, resulting in an initial underutilization of capacity, with the risk of the application crashing as its data grows toward the capacity threshold.

Thin provisioning, on the other hand, allows a storage administrator to allocate more capacity to specific applications or users than is physically available, under the assumption that not all those applications and users will need the entire allocated space simultaneously. This allows extra physical capacity to be installed at a later date as the total amount of space actually used approaches the current installed capacity.

"Thin provisioning is helping storage administrators break the old habit of overallocating storage, and is probably the most efficient way to reduce storage waste," said Mark Teter, CTO of Advanced Systems Group, a Denver-based storage and server solution provider.

Thin provisioning can yield huge savings by cutting the time and cost of allocating and administering storage, Teter said. "You can now have one storage administrator manage 200 Tbytes of storage," he said. "That's unthinkable without thin provisioning."

There's a definite return on investment with storage thin provisioning, said Pat Edwards, vice president of sales at Alliance Technology Group, a Hanover, Md., VAR.

For instance, Edwards said, it can allow a storage administrator costing $50,000 to $75,000 per year to be repurposed for other projects while cutting the spending on disks.

This is especially true in environments where customer data is growing fast, Edwards said. "The customers you need to pay attention to are those who are growing and have a need for automated management," he said. "If the customer's data is not growing fast, you can go in once in a while and check it. But if it's growing fast, it's a good candidate for thin provisioning."

The big payoff for customers is the ability to defer storage purchases, letting them take advantage of falling per-terabyte prices in the future, Teter said. Another benefit of thin provisioning is the "green" effect. "By cutting the disk capacity required while increasing disk efficiency, thin provisioning can also cut the carbon footprint of enterprise storage environments," he said.

Because of those benefits, thin provisioning is a fairly easy sell, said Greg Knieriemen, vice president of marketing at Cleveland solution provider Chi. "We can just ask our customers if they've had any downtime when expanding their applications," he said. "For a larger organization, that's a frequent situation with resource-hungry applications."

Thin provisioning can be an excellent tool for managing storage capacity and cost, said Keith Baskin, storage practice manager at Optimus Solutions, a Norcross, Ga.-based solution provider.

Oracle or SAP testing and development is a good application for thin provisioning because of a need for temporary storage space, Baskin said. However, the technology can also be dangerous when not used properly, he noted.

The biggest potential problem with thin provisioning is when it is used with Microsoft Windows NT File System, Baskin said. Files marked as deleted still maintain their original position. When an application saves new data in NTFS, it looks for unused data blocks, passing over "deleted" blocks in favor of blocks in which no data has been written.

Thin provisioning is not for every customer, said Rolf Strasheim, director of client solutions at Peak UpTime, a Tulsa, Okla.-based solution provider. For instance, it is not suitable for customers who do charge-backs based on storage capacity, Strasheim said.

Also, it is not a set-it-and-forget-it technology, Strasheim said. "If you put in thin provisioning and then walk away, it'll get you," he said. "It's not for clients that don't watch their storage. Thin provisioning notifies users as their capacity gets filled. But if they ignore the warnings, they'll drive right into a brick wall."

Thin provisioning, over time, will become more of a standard feature, Edwards said. "I don't know of any technology that could mitigate the need for thin provisioning," he said. "How can you discount a technology which gives customers more for less?"

Solution providers can choose from a variety of storage virtualization products offering some form of capacity management. The CRN Test Center examined solutions from four popular vendors to see how they stack up.

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