PowerEdge 2400 RAID performance

Hubbard, David dhubbard at dino.hostasaurus.com
Wed Aug 21 17:01:01 CDT 2002


From: jason andrade [mailto:jason at dstc.edu.au]
> 
> On Wed, 21 Aug 2002, Hubbard, David wrote:
> 
> > Yes, the solution is to use a different server or add a third
> > party raid controller in to the 2400's, the piece of garbage
> > that Dell calls a built-in raid controller on the 2400's
> > stinks, it is very effective at making $1500 in disks behave
> > like a slow IDE drive.
> 
> that's a little bit harsh dave :-)

It's harsh but true, check out my post from June of 2000 on this
very subject, the 2400's specifically:

http://lists.us.dell.com/pipermail/linux-poweredge/2001-June/000044.html

With three 10,000 rpm disks running in raid 5 on the built-in
RAID, I can achieve 4440kb/sec block writing speed.  I know
there is a raid 5 penalty, but I have a home-grown computer
at my house with two ATA/100 disks software mirrored, and I
can achieve 42 MB/sec with block writes there.  So, granted
there is a raid 5 penalty, but I can get ten times the performance
out of two disks that cost $65/each compared to my Dell server
with three drives that cost $400/each at the time, plus the
raid controller, etc.

Dave

> some advice/things to check
> 
> o are you using hardware raid in your 2400 ?
> 
> o how much memory do you have in it ? (memory helps, even with
>   write caching)
> 
> o if you are using the onboard raid, what stripe size did you use ?
> 
> o how poor is the performance on writes ? Megabytes/sec ? Kilobytes?
> 
> 
> regards,
> 
> -jason
> 




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