From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roger Heflin Subject: Re: What's the NFS OOM problem? Date: Tue, 15 Aug 2006 13:24:38 -0500 Message-ID: <44E21166.60308@atipa.com> References: <4ae3c140608081524u4666fb7x741734908c35cfe6@mail.gmail.com> <20060810045711.GI8776@1wt.eu> <17627.53340.43470.60811@cse.unsw.edu.au> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Willy Tarreau , Xin Zhao , linux-kernel , linux-fsdevel@vger.kernel.org Return-path: Received: from 125.14.cm.sunflower.com ([24.124.14.125]:65465 "EHLO mail.atipa.com") by vger.kernel.org with ESMTP id S1030447AbWHOSYa (ORCPT ); Tue, 15 Aug 2006 14:24:30 -0400 To: Neil Brown In-Reply-To: <17627.53340.43470.60811@cse.unsw.edu.au> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org Neil Brown wrote: > On Thursday August 10, w@1wt.eu wrote: >>> Can someone help me and give me a brief description on OOM issue? >> I don't know about any OOM issue related to NFS. At most it might happen >> on the client (eg: stating firefox from an NFS root) which might not have >> enough memory for new network buffers, but I don't even know if it's >> possible at all. > > We've had reports of OOM problems with NFS at SuSE. > The common factors seem to be lots of memory (6G+) and very large > files. > Tuning down /proc/sys/vm/dirty_*ratio seems to avoid the problem, > but I'm not very close to understanding what the real problem is. > > NeilBrown > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > I have noticed on SLES kernels that when the dirty_*ratios turned down it still uses alot more memory than it should work writeback buffers, it makes me think that with the default setting of 40% that it for some reason may be using all of memory and deadlocking. It does not seem like an NFS only issue, as I believe I have duplicated it with a fast lock setup. Checking writeback in /proc/meminfo does indicate that alot more memory is being used for write cache that should be. Roger