nfsiostat

$ nfsiostat

nfs.domain.com:/foo mounted on /foo:

   op/s         rpc bklog
 262.16
           0.00
read:
  ops/s            kB/s           kB/op         retrans         avg RTT (ms)    avg exe (ms)
                 11.557
        356.081
         30.812
       0 (0.0%)
          5.167
          5.239
write:
  ops/s            kB/s           kB/op         retrans         avg RTT (ms)    avg exe (ms)
                  3.620
        105.680
         29.190
       0 (0.0%)
         16.032
        331.458