On 04/06/2011 08:22 PM, Scott Carey wrote:
Simple power failure tests demonstrate that you lose data with these drives unless you disable the cache. Disabling the cache roughly drops write performance by a factor of 3 to 4 on G1 drives and significantly hurts wear-leveling and longevity (I haven't tried G2's).
Yup. I have a customer running a busy system with Intel X25-Es, and another with X25-Ms, and every time there is a power failure at either place their database gets corrupted. That those drives are worthless for a reliable database setup has been clear for two years now: http://www.mysqlperformanceblog.com/2009/03/02/ssd-xfs-lvm-fsync-write-cache-barrier-and-lost-transactions/ and sometimes I even hear reports about those drives getting corrupted even when the write cache is turned off. If you aggressively replicate the data to another location on a different power grid, you can survive with Intel's older drives. But odds are you're going to lose at least some transactions no matter what you do, and the risk of "database won't start" levels of corruption is always lingering.
The fact that Intel is making so much noise over the improved write integrity features on the new drives gives you an idea how much these problems have hurt their reputation in the enterprise storage space.
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