Tuning the gateway node on the NFS client

To tune the NFS client configuration on a gateway node, you can set the maximum number of (TCP) RPC requests. These RPC requests can be in-flight at a time by using the sunrpc.tcp_slot_table_entries or /proc/sys/sunrpc/tcp_slot_table_entries parameter.

For 1 GigE network, if the round-trip time is not set, keep the default value. You can increase the value to a number greater than 16 if the round-trip time is large. For 10 GigE network, ensure that this value is 48 or a number greater than 48 depending on the round-trip time.

When you set the seqDiscardThreshold parameter, it affects AFM or AFM DR as follows:
  • If I/O requests are from a node that is not the gateway node, this parameter does not affect AFM or AFM DR.
  • If the read request for an uncached file is on the gateway node, a higher seqDiscardThreshold value results in better performance. Because of this higher value, the gateway can cache more data. When the data is returned to the application, it is returned most probably from the cache or the primary cluster.

For more information about the seqDiscardThreshold parameter, see mmchconfig command.