sergey wrote:
I got a disk array appliance of 8 disks 1T each (UltraStor RS8IP4). It
will be used solely by PostgresQL database and I am trying to choose
the best RAID level for it.
..
Space is the least important factor. Even 1T will be enough.
Use RAID10, measure the speed of the whole array using the bonnie++ ZCAV
tool, and only use the fastest part of each array to store the important
stuff. You will improve worst-case performance in both sequential reads
and seek time that way. Drives are nearly twice as fast at their
beginning as they are at the end, and with only 8 drives you should be
able to setup a RAID10 array with all the fast parts aligned.
--
Greg Smith 2ndQuadrant US greg@xxxxxxxxxxxxxxx Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.us
"PostgreSQL 9.0 High Performance": http://www.2ndQuadrant.com/books
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