From: Bernd Schubert <bernd-schubert@web.de>
Subject: Re: async vs. sync
Date: Tue, 27 Jul 2004 00:06:04 +0200
Sender: nfs-admin@lists.sourceforge.net
Message-ID: <200407270006.08581.bernd-schubert@web.de>
References: <482A3FA0050D21419C269D13989C61130435E51E@lavender-fe.eng.netapp.com> <200407261905.40248.bernd-schubert@web.de> <41055FE5.3030206@bruvoll.com>
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> are you doing anything "interesting" underneath NFS, ie. what are you
> storing your files on?

Its similar to your configuration ;)

> My set-up has about the same performance data, however my big problem is
> that the server dies when I hook all my clients up... Raw throughput

=46ortunately that doesn't seem to happen in our case.

> seemed ok, but when you started complaining about the speed, I started
> thinking that my figures weren't all that great anymore.

At least its good to know that we are not alone. Well, I do know about the=
=20
performance decrease of sync-exports for a pretty long time, but I was neve=
r=20
sure if its not only a problem of our server (the previous one was a=20
PII-450).

>
> The set-up is a dual 3Ghz Xeon, 2Gb RAM, and a DRBD-mirrored partition
> sitting on a 3Ware Escalade 7500 to 7200rpm disks. Kernel

Here its a dual opteron, 3GB RAM, adaptec 79xx PCI-X scsi, transtec scsi-id=
e=20
raid. Local disk i/o is over 70MB/s. The server is connected with GBit, the=
=20
clients only with 100MBit. Here are some performace numbers when the server=
=20
was still running 2.6.7:

writing to /worka (async exported): 4 clients, all at full 11MB/s

writing to /home, (sync,no_wdelay exported): 4 clients at 7MB/s

(When I did the tests I was simply to lazy to test with more clients. Actua=
lly=20
I thought that 4 times 7 MB/s is more than sufficient for usual work).

The /home partition is also mirrored via drbd to a failover server, /worka =
is=20
not mirrored (mirroring 1.7TB is not that easy as mirroring 200GB ;) ).

So I really don't think that the server performance is the problem.

> 2.4.26-gentoo-r5, everything else newest version. The annoying thing is
> that the server this new set-up is replacing is an old P3/650 that
> easily copes with the load... :-\

Well, as I said, when I tested our old server with sync mounts, it had the=
=20
same problem. Are you sure that your old server did not export asynchronous?

Cheers,
	Bernd

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