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The real beauty of Flash Pool lies in the fact that NetApp's SSD caches work as fast for write operations as they do for read operations, said Timothy Abbott, general manager of the Irvine headquarters office of Irvine-based Trace3.
NetApp's previous Flash Cache technology was already one of the fastest implementations of SSD technology because it stored data in 4-KB blocks instead of 1-GB blocks, which rival EMC uses for its EMC FAST (Fully Automated Storage Tiering) technology, Abbott said.
That kind of granularity is important to storage efficiency, Abbott said.
"When you do storage tiering in 1-GB chunks, maybe only 10 percent of the capacity in those chunks is data being accessed, but you are still moving 1 GB of data," he said. "That's a big hit in performance. NetApp moves data in 4-KB chunks, which is much more efficient."
Flash Pool takes that one step farther by performing write operations to SSD cache devices at the same speed as read operations are done not only by using the smaller blocks but also by reading all data into the SSD and then moving what is not immediately required to spinning disk, Abbott said.
"With EMC FAST, the storage device looks at historical access to data and later migrates it to faster or slower storage based on historical data. NetApp, on the other hand, writes data as fast as it can to SSDs, and then moves it from there to spinning disk. NetApp does this in real time, not based on historical use," he said.
Flash Pool offers the ability to increase storage efficiency by using fewer disks, said John Woodall, vice president of engineering at Integrated Archive Systems, a Palo Alto, Calif.-based solution provider.
Other vendors migrate data between SSD and hard drive tiers on more of a manual basis, or based on specific schedules, Woodall said. However, he said, customers need to realize that it is not the right solution for every workload.
"Flash Pools are good," he said, but notes that it's "not a panacea. You must balance the technology against the cost. It will be right for some workloads. But it gives NetApp the parity it did not have before when adding Flash to storage arrays."