poor performances with Intel Raid Controller (iir)

[Julien Cigar]

On Fri, 2009-02-27 at 15:37 +0100, Wojciech Puchar wrote:
> >
> > 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.
> 

Not sure, I admit that the card is quite old (4 years), but 50 MB/s
seems really slow to me (especially for U320 SCSI) ..

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

I tend to use software RAID too (at least on system with multiple
processors)... when I have choice.


-- 
Julien Cigar
Belgian Biodiversity Platform
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