RAID Cards performance issue

[Scott Balneaves]

On Fri, Dec 05, 2008 at 12:24:49PM -0500, Nicolas Roussi wrote:
> Hi, I know that this topic is not the main subject matter of this list but I
> was wondering if anyone has any experience with RAID adapters and
> performance issues. I have already posted something on ubuntuforums.org (
> http://ubuntuforums.org/showthread.php?t=1001858). I would appreciate any
> input as to why the read speed on a 3ware 9650 RAID 5 would only be ~3MB/s
> and a PERC5 would be 10 times that much. Is there a way to troubleshoot this
> or maybe another benchmark for read and write speeds of my arrays?

Raid 5's terrible at a lot of things.  RAID5's essentially a huge compromise,
and doesn't really do ANYTHING well.  See:
http://en.wikipedia.org/wiki/RAID5#RAID_5

You'd be far, FAR better off with something like RAID0, or RAID10.  You lose
half your drive space, but drives are cheap, and the performance gains are
huge.

Scott

-- 
Scott L. Balneaves | Today's weirdness is tomorrow's reason why.
Systems Department |    -- Hunter S. Thompson
Legal Aid Manitoba |