From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rich Subject: Re: poor nfs performance & hangs with latest kernels Date: Tue, 20 Feb 2007 14:45:02 +0200 Message-ID: <45DAED4E.4050504@hq.vsaa.lv> References: <45D9B915.2010305@hq.vsaa.lv> <17882.49990.799201.335846@notabene.brown> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Cc: nfs@lists.sourceforge.net To: Neil Brown Return-path: Received: from sc8-sf-mx1-b.sourceforge.net ([10.3.1.91] helo=mail.sourceforge.net) by sc8-sf-list2-new.sourceforge.net with esmtp (Exim 4.43) id 1HJUMt-0000F0-Q2 for nfs@lists.sourceforge.net; Tue, 20 Feb 2007 04:45:18 -0800 Received: from [81.198.191.135] (helo=ns1.vsaa.lv) by mail.sourceforge.net with esmtp (Exim 4.44) id 1HJUMv-0005Yi-2v for nfs@lists.sourceforge.net; Tue, 20 Feb 2007 04:45:17 -0800 In-Reply-To: <17882.49990.799201.335846@notabene.brown> List-Id: "Discussion of NFS under Linux development, interoperability, and testing." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: nfs-bounces@lists.sourceforge.net Errors-To: nfs-bounces@lists.sourceforge.net Neil Brown wrote: > On Monday February 19, rich@hq.vsaa.lv wrote: ... >> when there is some intensive nfs activity (write), all other nfs >> operations slow down to crawl or even stop at all during that time. >> >> i have been able to reproduce the problem with kernel versions >> 2.6.16.40, 2.6.19.2 and 2.6.20 (on slackware-11.0). >> another person reproduced the hang with 2.6.19-1.2911.fc6 (fedora core 6). > > Are there any kernels where you cannot reproduce the problem? well, now that my localhost tests are invalidated, i will have to do additional testing :) ... >> export a local directory. i'm using >> localhost(rw,no_root_squash,sync,no_subtree_check). >> mount it locally and try to perform a write operation : >> dd if=/dev/zero of=/mounted_nfs/testfile bs=512k count=2048 > > This scenario is known to cause problems, is very hard to fix, and is > a case of "well don't do that then". The problems here are probably > unrelated to the problems you are having between separate machines. there i was, hoping to have found a reliable method to reproduce the problem... btw, what's the main cause for this problem ? could it also be observed on fast networks or is it limited to cases when server & client are on the same machine ? >> using 2.6.16.21, i was unable to hang my workstation, but server, even >> though it survived the test, is still having excessive load (~ 4). top >> lists as most resource hungry processes nfsd, kjournald and >> kblockd. > > So 2.6.16.21 survives but 2.6.16.40 doesn't? Is that a reliable > result? Is that with separate server and client, or server and client > on the same machine? most tests were done on a single machine (3 different ones, though), after i observed initial problems between several clients and single server. so now i will have to redo all the tests with separate client & server machines :) > NeilBrown -- Rich ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ NFS maillist - NFS@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nfs