[CentOS] disk I/O problems with LSI Logic RAID controller

nate centos at linuxpowered.net
Tue Feb 9 21:53:50 UTC 2010

Fernando Gleiser wrote:

> yes, ita bunch of 12 7k2 RPM disks organized as 1 hot spare, 2 parity disks,
> 9 data disks in a RAID 5 configuration. is 9/2 a "high ratio"?

Perhaps RAID 6, as I've never heard of RAID 5 with two parity (two
parity is dual parity which is RAID 6).

RAID 6 performance can vary dramatically between controllers, if it
were me unless you get any other responses shortly I would test other
RAID configurations and see how the performance compares

RAID 1+0
RAID 5+0 (striped RAID 5 arrays, in your case perhaps 3+1 * 4 w/no hot
 spares? at least for testing)
RAID 5+0 (5+1 * 2)

RAID 1+0 should be first though, even if you don't end up using it
in the end, it's good to get a baseline with the fastest configuration.

I would expect the RAID card to support RAID 50, but not all do, if it
doesn't one option may be to perform striping using LVM at the OS


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