[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
level.

nate



More information about the CentOS mailing list