Re: amr Serious performance issues

[Hans Rosenfeld <hans%NetBSD.org@localhost>]

On Tue, Jan 11, 2011 at 04:06:20PM +0100, Manuel Bouyer wrote:
> On Tue, Jan 11, 2011 at 03:09:03PM +0100, Hans Rosenfeld wrote:
> > Have you used a MegaRAID recently with 5.1?
> > 
> > I have a similar performance issue with an AMI MegaRAID SCSI 320 without
> > write cache. On a RAID5 of 4 73GB disks I get about 6MB/s write speed.
> > Until recently I believed that this just old hardware and lack of write
> > cache. Then I found out that Linux does about 27MB/s on the same hardware
> > and configuration.
> 
> Are partitions aligned in the same way ?

I don't remember whether I used any partitions at all. The machine is
currently down and far away, so I can't check that right now. I think
most of the time I tested with dd directly to the raw device, using
block sizes 128k and 512k. Is a specially aligned partitioning supposed
to make that much of a difference?


Hans


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