From: Martin Knoblauch Subject: Strange NFS write performance Linux->Solaris-10/VXFS, maybe VW related Date: Fri, 28 Dec 2007 07:24:59 -0800 (PST) Message-ID: <713696.79839.qm@web32608.mail.mud.yahoo.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-nfs@vger.kernel.org To: linux-kernel@vger.kernel.org Return-path: Sender: linux-kernel-owner@vger.kernel.org List-ID: Hi, currently I am tracking down an "interesting" effect when writing to a Solars-10/Sparc based server. The server exports two filesystems. One UFS, one VXFS. The filesystems are mounted NFS3/TCP, no special options. Linux kernel in question is 2.6.24-rc6, but it happens with earlier kernels (2.6.19.2, 2.6.22.6) as well. The client is x86_64 with 8 GB of ram. The problem: when writing to the VXFS based filesystem, performance drops dramatically when the the filesize reaches or exceeds "dirty_ratio". For a dirty_ratio of 10% (about 800MB) files below 750 MB are transfered with about 30 MB/sec. Anything above 770 MB drops down to below 10 MB/sec. If I perform the same tests on the UFS based FS, performance stays at about 30 MB/sec until 3GB and likely larger (I just stopped at 3 GB). Any ideas what could cause this difference? Any suggestions on debugging it? spsdm5:/lfs/test_ufs on /mnt/test_ufs type nfs (rw,proto=tcp,nfsvers=3,hard,intr,addr=160.50.118.37) spsdm5:/lfs/test_vxfs on /mnt/test_vxfs type nfs (rw,proto=tcp,nfsvers=3,hard,intr,addr=160.50.118.37) Cheers Martin PS: Please CC me, as I am not subscribed. Don't worry about the spamtrap name :-) ------------------------------------------------------ Martin Knoblauch email: k n o b i AT knobisoft DOT de www: http://www.knobisoft.de