Here a list a settings to change to properly accomodate NFS on an Iomega StorCenter Pro NAS:
- NFS.MaxVolumes = 32
- NFS.HeartbeatFrequency = 12
- NFS.HeartbeatTimeout = 5
- NFS.HeartbeatMaxFailures = 10
- Net.TcpipHeapSize = 30
The three heartbeat options control heartbeat counts and timeouts. In the event of a brief network connection loss, reboot, or failure of the NFS server, the ESX Server will not simply fail the NFS datastores. The NFS client in ESX relies on heartbeats to verify the NFS shares are available. Therefore, increasing theNFS heartbeat frequency will ensure the NFS datastore I/O can resume much sooner, once the NFS server comes back.
The TCP/IP heap is memory used for TCP/IP buffers for NFS. The default NFS.SendBufferSize is 264KB, and the default NFS.ReceiveBufferSize is 128KB. So with two sockets per volume, the total heap needed per volume is 784KB. If you want to create a total of 32 NFS datastores, then you need approximately 25MB in heap size. If you set the heap size to 30MB, you will ensure the best NFS datastore performance when the maximum number of datastores are created.