Is solid-state storage a good complement for mechanical HDD arrays in a SAN to negate I/O
bottlenecks in some applications?
Solid-state disks are a great solution for very high activity file systems, like database transaction logs. Some of the storage vendors allow you to use a portion of the subsystem cache inside the SAN storage array as a solid-state disk. The data is "pinned" into cache that guarantee's a cache hit for every read. As cache memory is thousands of times faster than a spinning disk and makes for a great solution for high performance applications.
The only bad part of using subsystem cache as a solid state disk, is that the portion of cache you use is dedicated to that application and not available for use by other systems connected to the array. The good news is the cache is usually backed up by a raid volume, and the data in cache can be flushed down to disk is a power outage occurs.
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This was first published in November 2002