nfs client speed lower than expected.

Vincent Hoffman vince at
Thu Nov 3 10:07:31 UTC 2011

[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-60.2 sec  6.22 GBytes   887 Mbits/sec

transfers in via ssh are nice and nifty too.


On 02/11/2011 23:55, Gary Gatten wrote:
> Is the interface really at 1Gb?  Have you tested with iperf, ftp, or anything other than nfs?
> -----Original Message-----
> From: owner-freebsd-questions at [mailto:owner-freebsd-questions at] On Behalf Of Vincent Hoffman
> Sent: Wednesday, November 02, 2011 6:52 PM
> To: FreeBSD-Questions at
> Subject: nfs client speed lower than expected.
> Hi all,
>         What kind of speed should I be expecting over an NFS mount from
> a linux box using a gig interface (igb)? I'm seeing linux clients
> getting approx 2 or 3 times the throughput rsyncing files from a linux
> nfs server that i get from a 8-stable FreeBSD client.
> representative results
> 7.26MB/s - Freebsd client
> 21.10MB/s liunx client
> I've tried a variety of files to try and take caching out of the
> equation, I've tweaked a few sysctls after much googling
> kern.ipc.maxsockbuf=4000000
> net.inet.tcp.sendbuf_max=16777216
> net.inet.tcp.recvbuf_max=16777216
> net.inet.tcp.sendbuf_inc=16384
> net.inet.tcp.recvbuf_inc=524288
> net.inet.udp.recvspace=65535
> with no obvious improvement.
> freebsd mount options
> ro,noatime,noexec,nosuid,udp,nfsv3,rsize=1024,wsize=1024,bg,hard,intr,timeout=4,retrans=4
> linux mount options
> _netdev,ro,noatime,nodev,noexec,nosuid,proto=udp,vers=3,rsize=1k,wsize=1k,bg,hard,intr,timeo=4,retrans=4
> I have seen that using the linux server as an nfs client to write to the
> NFS server on the freebsd box gives similar performance to a linux
> client pulling from the linux server so I'm guessing its something to do
> with the freebsd nfs client?
> Any suggestions/clues welcome.
> Thanks,
> Vince
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