[CentOS] kernel: nfs: RPC call returned error 88

We have a 2-node Oracle RAC that keeps getting the following error: kernel: nfs: RPC call returned error 88

The storage being mounted is netapp. We don't see any errors/issues on the storage itself or the switches this client is connecting thru. The NFS network is a 2-interface ( 2 x 1Gb UTP) bond which shows no errors of any kind.

We are mounting with the following mount options: rw,noac,nointr,bg,hard,timeo= 600,wsize=32768,rsize=32768,nfsvers=3,tcp

This problem sometimes hits the OCR votedisk shares and causes the instance to crash.

These systems were upgraded to 5.6 back in January.

Currently running 2.6.32-300.4.1.

Thanks for any info,