Re: async vs. sync

[Bernd Schubert <bernd-schubert@web.de>]

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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

Fortunately 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 
performance decrease of sync-exports for a pretty long time, but I was never 
sure if its not only a problem of our server (the previous one was a 
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-ide 
raid. Local disk i/o is over 70MB/s. The server is connected with GBit, the 
clients only with 100MBit. Here are some performace numbers when the server 
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. Actually 
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 
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 
same problem. Are you sure that your old server did not export asynchronous?

Cheers,
	Bernd

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