Re: Re: mkfs options for a 16x hw raid5 and xfs (mostly large files)

[Justin Piszcz <jpiszcz@xxxxxxxxxxxxxxx>]

On Wed, 26 Sep 2007, Ralf Gross wrote:

> Justin Piszcz schrieb:
> > >  /sbin/blockdev --setra 16384  /dev/sdc
> > >
> > > was the key to ~400 MB/s read performance.
> > Nice, what do you get for write speed?
> Still 170-200 MB/s. The command above just tunes the read ahead value.
>
> Ralf
Yes, I understand; what is the equivalent tweak for HW RAID? I have tried 
to tweak some HW RAIDS (3ware 9550SX's) with ~10 drives and one can set 
the read ahead for better reads but writes are still slow, that 3ware 
'tuning' doc always get passed around but it never helps much at least in 
my testing.
I wonder where the bottleneck lies.

Justin.