Very Poor Raid Card Performance

Ivan Voras ivoras at
Tue Jan 16 22:01:03 UTC 2007

Steven Lowry wrote:

> The main problem is my HD performance, it is approx 6x slower than in
> windows XP, hopefully there is a solution. I have an LSI Megaraid 8x with
> four drives in a raid 5 configuration, in windows I was getting upto 60MB/s
> transfer rates but in FBSD I am getting upto 9MB/s. I followed the
> instructions in the handbook for tuning disks and I have set dma on.
> Being new to unix, I have no idea what to try or get system information
> too continue troubleshooting.
> If anyone could point me in the right direction or to appropriate
> documentation it would be much appreciated.

First, you could try asking the question at performance/at/
mailing list - you could get more help there.

This reminds me of something I've seen on a box that's also equipped
with LSI Megaraid but since disk I/O wasn't important for it, I didn't
dig further and forgot about it. Maybe the driver has a problem and
people on the performance list can help you.

Here's a general checklist of what information to gather before sending
it to performance list:

* dmesg snippet (like you sent)
* copy with "cp" in console, not with KDE and see if it changes anything
* run 'iostat' while copying and send results
* install and run "bonnie++" (disk I/O benchmark) and send results

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