Date: Wed, 28 Mar 2012 17:35:47 -0400 (EDT) From: Rick Macklem <rmacklem@uoguelph.ca> To: Sven Brandenburg <sven@crashme.org> Cc: freebsd-fs@freebsd.org Subject: Re: NFSv3, ZFS, 10GE performance Message-ID: <1023490904.1870197.1332970547582.JavaMail.root@erie.cs.uoguelph.ca> In-Reply-To: <4F709A18.50907@crashme.org>
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Sven Brandenburg wrote: > On 03/26/2012 12:37 PM, Ivan Voras wrote: > > You could try modifying the rsize and wsize NFS options (read > > mount_nfs(8)), they help with UFS. > > I tried this a few days ago and fiddling rsize alters performance from > "ok" to "terrible". > However, you made me revisit this and mount_nfs(8) seems to have a gem > in its options: readahead. > This did the trick for me and my (long and sequential) reads. > While the manpage says its limited to 0-4, the best results were > achieved with readahead=8 : 1.1GB/s - which is what I had hoped for. > Yea, the new NFS client allows a readahead of up to 16. The man page for FreeBSD-9 should probably be changed, since the new NFS client is the default. Btw, without readahead, the client will do Read RPCs serially. (In other words, the next Read RPC won't start until the reply to the previous one has been received.) > On a tangent: gnu-dd 1GB/s is 10^9 Bytes/s, not 2^30. Yes, I fell for > it > at first :) > The good news is that there was no fiddling on the NFS server side. > (Apart from MTU increases, PCI settings and more buffers to get TCP > performance to full tilt in the first place) > > Hopefully, readahead doesn't kill performance for smaller files.. :-) > Well, readaheads only happen if the file is large enough for the readahead to be before EOF. As such, they just won't happen for small files. rick > regards, > Sven > _______________________________________________ > freebsd-fs@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-fs > To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org"
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