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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)	[thread overview]
Message-ID: <> (raw)


 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 (, 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=
spsdm5:/lfs/test_vxfs on /mnt/test_vxfs type nfs (rw,proto=tcp,nfsvers=3,hard,intr,addr=

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

             reply	other threads:[~2007-12-28 15:25 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-12-28 15:24 Martin Knoblauch [this message]
2007-12-28 18:45 ` Strange NFS write performance Linux->Solaris-10/VXFS, maybe VW related Chris Snook
2007-12-29  9:59 Martin Knoblauch
2007-12-29 11:11 Martin Knoblauch
2008-01-14  8:01 Martin Knoblauch

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