From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Bruvoll Subject: Re: async vs. sync Date: Tue, 27 Jul 2004 13:00:05 +0100 Sender: nfs-admin@lists.sourceforge.net Message-ID: <410643C5.3040004@bruvoll.com> References: <482A3FA0050D21419C269D13989C61130435E51E@lavender-fe.eng.netapp.com> <200407261905.40248.bernd-schubert@web.de> <41055FE5.3030206@bruvoll.com> <200407270006.08581.bernd-schubert@web.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Cc: NFS mailling list Return-path: Received: from sc8-sf-mx1-b.sourceforge.net ([10.3.1.11] helo=sc8-sf-mx1.sourceforge.net) by sc8-sf-list2.sourceforge.net with esmtp (Exim 4.30) id 1BpQd4-0002pL-5b for nfs@lists.sourceforge.net; Tue, 27 Jul 2004 05:00:22 -0700 Received: from homer.brvl.com ([213.61.99.172]) by sc8-sf-mx1.sourceforge.net with esmtp (TLSv1:AES256-SHA:256) (Exim 4.34) id 1BpQd3-00054e-DY for nfs@lists.sourceforge.net; Tue, 27 Jul 2004 05:00:22 -0700 To: Bernd Schubert In-Reply-To: <200407270006.08581.bernd-schubert@web.de> Errors-To: nfs-admin@lists.sourceforge.net List-Unsubscribe: , List-Id: Discussion of NFS under Linux development, interoperability, and testing. List-Post: List-Help: List-Subscribe: , List-Archive: Bernd Schubert wrote: >>are you doing anything "interesting" underneath NFS, ie. what are you >>storing your files on? >> >> > >Its similar to your configuration ;) > > Good :-) >>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. > > Let me clarify - the server doesn't quite die, however it slows down drastically, having a load of ~7 while 99% CPU idle. The clients clog up, and for instance trying to mount anything just times out. If I unmount the busy share from the clients, everything settles down again. >>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. > > I tried a little more performance number hunting: - NFS copy and write to same device - 3Mb/s sustained (500Mb file) - piozone direct write to RAID device - ~34-50Mb/s (depending on file size) - drbd network device - 933Mb/s Nothing really wrong here I'd say - not blazingly quick, but surely nothing to explain why everything just stops when I hook up my 12 clients to this set-up? >>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? > > Doesn't seem so, no, the /etc/export is -extremely- simple: /export client1(rw,no_root_squash) Similarly, I'm not trying to be clever on the client side (/etc/fstab excerpt): server:/export /export nfs rw,hard,intr 0 0 This set-up works wonderfully on the old 2.4.17 box, but grinds to a halt on the new ones :-( Regards Jan ------------------------------------------------------- This SF.Net email is sponsored by BEA Weblogic Workshop FREE Java Enterprise J2EE developer tools! Get your free copy of BEA WebLogic Workshop 8.1 today. http://ads.osdn.com/?ad_id=4721&alloc_id=10040&op=click _______________________________________________ NFS maillist - NFS@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nfs