poor performances with Intel Raid Controller (iir)

[Wojciech Puchar]

>
> I've a machine with an integrated Intel RAID controller (U320) which
> uses the iir driver. I have two arrays, one RAID 1 with two disks and
> one RAID 5 with 8 disks. The disks are all Seagate 320MB/s. The system
> is running FreeBSD 7.0-RELEASE with 8 processors (2,40 Ghz) and 4GB or
> RAM.
>
> I have very poor performances, around ~50 MB/s, is it normal ?
>
> jcigar at bccm-it ~ % dd if=/dev/zero of=blah bs=10M count=100
> 100+0 records in
> 100+0 records out
> 1048576000 bytes transferred in 20.168689 secs (51990290 bytes/sec)
>
> Are there any tool to detect what could be the bottleneck(s) ?

are you sure it isn't NORMAL performance of this card.

i think it is, the "hardware" RAID solutions are usually much slower than 
software, even more with RAID5.