nfs client speed lower than expected.

Vincent Hoffman vince at
Thu Nov 3 10:24:46 UTC 2011

I'll give it a try when i get a moment, These servers are all on gigabit
LAN (sadly 1500 mtu until I can get the network guy to schedule an
outage to reboot the switches and enable jumbo frames,) same subnet so i
would expect UDP to have similar or better performance.


On 02/11/2011 23:53, Michael Sierchio wrote:
> Mount via tcp.
> On Wed, Nov 2, 2011 at 4:51 PM, Vincent Hoffman <vince at> wrote:
>> 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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