Subject: Re: linux NFS client
From: Christopher E. Brown (cbrown@woods.net)
Date: Thu Apr 24 2003 - 12:57:59 AKDT
On Thu, 24 Apr 2003, volz wrote:
>
> We have been noticing poor writes to our WindowsPowered NAS (~.5 Mb/sec). The
> shared disks on the server are NFS mounted to linux clients running 2.4.18
> kernels. It is well documented that earlier versions of linux NFS performed
> poorly with servers running other OS's, including Solaris and Irix. We have
> validated these results, linux to linux screams, but linux client writes to
> solaris/windows bites.
>
> So far the things we have tried are:
>
> - We have mounted the server -o
> hard,intr,rsize=[default|4096|8192],wsize=[default|4096|8192],vers=3
>
> Does anyone know whether newer kernels or stable patched linux kernels address
> this problem? And what type of performance Trond's latest patched kernels are
> capable of?
I would suggest updating to the latest 2.4 release, there were more
than a few cleanups in 2.4.19 and 2.4.20, dealing with NFSv3 interop.
Also, grabbing the latest nfs-utils would be a good idea.
Do you know what NFS stack the windows NAS is running? Many of the
NFS add-ins for other OSes are Sun NFS based.
Sun wrote the book on NFS, and as such they have never bothered much
with tuning for anything but Sun<->Sun. There has been a history of
performance issues, and not just with Linux when mixing with Sun NFS,
it seems to crop up every time there is any real revision (such as the
NFS2->NFS3 changeover). Unfort NFS is a complex thing, and minor
timing differences, command ordering, and things like exactly how a
server handles commit orders in a combined write cache situation (even
if both systems follow the spec, there is room to roam) can cause
interesting stalls.
As of late 2.4 NFSv3, Linux to Linux screams, and Linux to
(current) HP/UX, IRIX, and most current *BSD systems seems to work
well. (Example, tested NFSv3(wsize/rsize=8192) Linux - Linux
9.5MB/sec, HP/UX (client) - Linux (server) 8MB/sec, HP/UX (client) -
HP SAN 8.5MB/sec, Linux (client) - HP SAN 8MB/sec, certainly
workable for a 100Mbit network).
You may want to try bumping wsize/rsize to 32768 (Sun NFSv3 based is
known to do better with 32k even if average reads/writes are smaller
than this). Also, checking the IP stack on the Windows NAS might not
be a bad idea. By default the buffers are fairly small, and that can
prevents systems from streaming well.
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This archive was generated by hypermail 2a23 : Thu Apr 24 2003 - 12:56:29 AKDT