[linux-lvm] Re: lvm2 performance data with linux-2.6
Mark Wong
markw at osdl.org
Thu Mar 11 17:23:02 UTC 2004
On Thu, Mar 11, 2004 at 05:12:35PM -0500, Bill Davidsen wrote:
> markw at osdl.org wrote:
> > I've started collecting various data (including oprofile) using our
> > DBT-2 (OLTP) workload with lvm2 on linux 2.6.2 and 2.6.3 on ia32 and
> > ia64 platforms:
> > http://developer.osdl.org/markw/lvm2/
> >
> > So far I've only varied the stripe width with lvm, from 8 KB to 512 KB,
> > for PostgreSQL that is using 8 KB sized blocks with ext2. It appears
> > that a stripe width of 16 KB through 128KB on the ia64 system gives the
> > best throughput for the DBT-2 workload on a volume that should be doing
> > mostly sequential writes.
> >
> > I'm going to run through more tests varying the block size that
> > PostgreSQL uses, but I wanted to share what I had so far in case there
> > were other suggestions or recommendations.
> >
> Here's one thought: look at the i/o rates on individual drives using
> each stripe size. You *might* see that one size does far fewer seeks
> than others, which is a secondary thing to optimize after throughput IMHO.
>
> If you don't have a tool for this I can send you the latest diorate
> which does stuff like this, io rate perdrive or per partition, something
> I occasionally find revealing.
Yeah, please do send me a copy. I'd be interested to see what that might
turn up. I've just been using iostat -x so far.
Thanks,
Mark
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