Re: nfs4 mount options rsize wsize
Hi Klaus,
many thanks for sharing your experience!
On Mon, May 20, 2013 at 12:28:24PM +0200, Klaus Knopper wrote:
> We have been running NFS over WLAN, and experienced problems that turned
> out to be related to bufferbloat
> (http://en.wikipedia.org/wiki/Bufferbloat) in combination with low
> bandwidth.
[...]
>
> The solution after many tests was at first somewhat surprising: We
> reduced rsize and wsize to a very small value (4096), and set mount
> options to "sync", which is known to be very slow on local file systems,
> but resulted in a big performance boost when used on NFS. After the
> changes, Bandwidth was equally shared amongst all clients with no more
> timeouts and sudden logouts.
>
> While a single workstation surely has a somewhat lower data throughput,
> the entire class of 20+ Desktops connected as NFS clients was
> operational again.
>
> >From this experience, we created a HOWTO which you can still find at
> https://rp.skolelinux.de/rlp-wiki/bin/view/RlpSkolelinuxPublic/NetworkPerformanceTuning
> (I sent this link before in a different context).
>
> Also, we used a local NFS cache (mount option fsc) which is only
> possible with new kernels and xattr file system support. This option
> lowers network bandwidth peaks somewhat when reading parts of files that
> were just written from a client. But the "sync" option and smaller rsize
> and wsize were actually the client options that gained the biggest
> performance boost.
Did all this happen with NFSv4 or was this still NFSv3? My impression
is that with NFSv4, quite some stuff has been changed and improved, for
example 'sync' is the default and recommended option.
Best regards,
Andi
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