Disk Enclosures
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Write Cache for DB or Exchange

Ayman Altounji
Valued Contributor

Write Cache for DB or Exchange

Is it save, to enable the write cache of the array controller for SQL (6.5, 7.0, 2000) or Exchange Data base ?
Any known problems with the array driver when it write back the data to the cache of the array controller and read the "same" data back (data are in cache and not yet on disk).
thanks for any info
Ayman Altounji
Valued Contributor

Re: Write Cache for DB or Exchange

hi k-weibel

YES it IS SAVE. the smart 53xx has a battery backed cache which will keep your data up to 4 days alive and will automatically write them back to the disks after a power outage.
espacially under randonm i/o (typical for databases) a read/write cache can give you up to 40 % of extra performance (my own benchmarks showed this - using ml370g2 with smart 5304 and intels iometer benchmark).
the write cache of compaq shipped hot-plug disks is disabled as a default so the whole thing is really save ...
and if the hw breaks (cache, controller) nobody will guarantee for anything because broken hw can really behave strange. this is why you need a backup even if you would use super-dupa raid technology.

ernesto from germany