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The expanding tiered storage model

The tiered storage model is growing, with solid-state drives (SSDs) at the top and cloud backup at the bottom. Find out how these two storage tiers can fit into your storage infrastructure, and learn about changes within the other tiers of storage.

The tiered storage model is growing, with solid-state drives (SSDs) grabbing a lot of attention at the top -- in the tier 0 slot -- and cloud backup joining the ranks at the bottom of the pyramid.

A solid-state drive can pump out double the IOPS of a SAS or SATA drive, and SSDs use as much as 50% less power than typical disks. Cost is still the prohibitive factor, but they have dropped as much as threefold in the last year.

Still, despite the increasing popularity of SSDs, the majority of users are still relying on tier 1 and traditional spindle drives for high performance, said Greg Schulz, founder and senior analyst at Stillwater, Minn.-based StorageIO Group. "Tier 1 remains the primary high-performance tier," he said. "People aren't adopting solid state as fast as the rhetoric would have you believe."

A June 2009 tiered storage survey of Storage magazine readers supports that assertion: Only 12% of respondents said they use SSDs for high-performance applications. Solid-state drives, which are sold by companies such as STEC Inc. and Texas Memory Systems Inc., are hard to justify if you depend on a gigabyte-capacity-per-dollar analysis because of the technology's high cost and low capacity.

Meanwhile, the higher capacity but lower performing 3.5-inch SATA drives on tier 2 can hold up to 2 TB of data, while 2.5-inch drives can hold up to 500 GB, noted Schulz. Add smarter, second-generation power management features on today's storage systems, and it's clear that mechanical disks won't go down without a fight.

And the most game-changing advances in the tiered storage model might be at the bottom of the pyramid, where cloud services and virtual tape libraries (VTLs) offer administrators more scale-out options for archiving and storing little-used data.

Jeff Boles, senior analyst and director of validation services at Hopkinton, Mass.-based Taneja Group, said both public and private clouds show potential in the archiving tier because the cost per gigabyte of storage is very low. In addition, the point of entry for vendors and IT organizations is very low. Public clouds offer the most savings, but less control and security. Private clouds put you in control, but with more costs, and implementation and management responsibilities.

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