Re: PowerEdge 2650 and Perc3/DI

Peter Dieth wrote:

> we are experiencing disappointing RAID5 performance of
> our brand new PowerEdge 2650 server.

RAID 5 is not to get speed, it's to get redundancy.
And raid_5 is the raid level that gets the lowest speed.

> We are running RHEL3 using a static SMP kernel and the newest
> aacraid driver:

Red Hat does not support own kernels, look what Red Hat kernel
maintainers say:
http://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=101650

"Unsupported.  Red Hat does not support 3rd party kernel modules
in any way, wether they are proprietary/binary only, open source,
GPL, or otherwise.  We also do not support user compiled kernels
or kernel modules.  We only support the binary kernel we ship,
with the binary modules we ship.  This includes patched sources
as well as unmodified sources."

So, if you have any problem with RHEL then contact with RH guys.

> Is disabling the ROMB (raid on mother board) and running
> software RAID a better solution concerning performance
> and stability?

more performance yes. Stability is the same if your aacraid/PERC
set is stable.

> Is configuring the 4 harddisks as one RAID1 volume
> a solution to get much more performance? If yes:

try to run raid 1+0, or 0+1, with the PERC board.
And then raid_5 and raid_1+0 with linux_sw_raid

> would it ever be faster than software RAID?

Linux_soft_raid is very fast. To get same performance with
HW you have to buy a *high* class board with a Xscale >600Mhz
chip.

> Are there any other options?

HW raid or SW raid :-)


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