Centos – Very very slow NFS performance

centosnfsubuntu-10.10

I'm having a quite strange issue. I'm mounting a NFS share from a SAN (ubuntu) to another machine (centos)

Mounting the share works just fine; but when I try some tests like : 

dd if=/dev/zero of=bigfile bs=1k count=2000
2000+0 records in
2000+0 records out
2048000 bytes (2.0 MB) copied, 16.7555 seconds, 122 kB/s

On clientside, network has MTU 9000; i can successfully ping -s 8000 at least the server.

On SAN side it has 4 Gigabit interfaces bonded.

Both sides run NFS4; mounting using : 

mount -t nfs4 192.168.3.3:/share /myshare/

Where should I start investigating ?

And what is the average transfer rate I could accept ? 50 Mb/s for a single gigabit connection ?

edit:
server exports : 

/export/share *(rw,insecure,async,no_subtree_check)

edit:
local storage test

time dd if=/dev/zero of=bigfile2 bs=1k count=200000
200000+0 records in
200000+0 records out
204800000 bytes (205 MB) copied, 0.509998 seconds, 402 MB/s

real    0m0.558s
user    0m0.009s
sys 0m0.546s

Best Answer

You could try using different mount options than the defaults. Might be worth trying the following using the mount -o option and rerunning your dd test.

rw,bg,hard,nointr,rsize=32768,wsize=32768,tcp,timeo=600,actime=0

Try reading man nfs for details on the mount options and what they mean.

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