Redundant NFS storage setup (part 3) : The disappointing PERC5/E

[Tino Schwarze]

On Thu, Jan 03, 2008 at 01:04:08PM +0100, Matthias Saou wrote:

> > I would suggest testing with a stripe size of 64kb instead of 128kb. We 
> > are currently testing our HP servers with a P800 with similar 
> > dissapointment, but found out that anything above a stripe size of 64kb 
> > absolutely kills the performance (ofcourse no one would tell us that). I 
> > believe it's based on a similar chip that the PERC5/E has.
> 
> I've just tested with 64k stripe size. Read speed is still
> disappointingly low... 50-60MB/s where software RAID gives 310-330MB/s.
> 
> It seems like this is even less than with 128k stripe size, with a
> single non-cached file read I get 80-110MB/s now, had up to 250MB/s
> with 128k stripe size and... 320MB/s with software RAID.
> 
> But to be 100% sure, I need to wait for the background initialization
> to finish, which will take a few hours. I'm not holding my breath,
> though.

Are you using the latest megaraid_sas? I've seen speed improvements
using the new driver.

Tino.

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