Re: nfs performance problem

["Ragnar Kjørstad" <nfs@ragnark.vestdata.no>]

On Tue, Nov 05, 2002 at 08:55:41PM +0100, poczta.dotcom.pl wrote:
> > How is local performance?
>=20
> local read/writes are ok
>=20
> > What filesystem do you use?
>=20
> reiserfs on top of  lvm (to be able to get snapshots)

What reiserfs-version? 3.5 or 3.6?=20
What on-disk format? 3.5 or 3.6?
There should be an entry in the kernel-log from when the filesystem is
mounted.=20


Reiserfs-3.5 has some known performance-problems related to NFS - that
may be your problem.


> > What's the output from "iostat -x -d -k 60 3"?
> >
> below is output from 'iostat -d 60 3'  (- my iostat does not take '-k'
> option,
> and '-d' gives me empty output) - mayby this is enough?

And not -x either?
iostat fr=E5 sysstat-4.0.3-2 (from RedHat) includes a "-x" option for
extended output. Most importantly, it will tell how much of the time
each device is busy.

It's unclear from your posts if this is a io-related problem or not.
Unnless you're running reiserfs-3.5 my guess is that it is the
IO-performance that is the problem. 3ware 7500 controllers have rather=20
poor performance on RAID5 - especially for writes.=20

If that's correct, then switching to a different RAID-level or replacing
the 3ware-controller should solve the problem. SCSI- or FC- RAIDS are
easily 10 or 20 times faster than the 3ware RAID for some types of
operations, and if you want something cheaper there is also different
types of IDE-RAIDs.



--=20
Ragnar Kj=F8rstad
Big Storage


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