Tuning for Kernel NFS backend on AFM and AFM DR

If AFM communication use the NFSv3 protocol, for peak performance, tune the gateway NFS servers that host home exports and the gateway servers that support cache/primary filesets.

Most of these tuning parameters require at least the AFM client to be restarted. Ensure that the NFS server is not mounted. Unlink the AFM fileset, or stop GPFS or IBM Spectrum Scale on the gateway node.

Tuning for 1GigE networks is different from tuning 10GigE networks. For 10GigE, all settings need to be scaled up, but not necessarily by a factor of 10. Many of these settings are affected after a server reboot. Therefore, each time a server restarts, the settings must be reset. The TCP buffer tuning is required for all 10GigE links and for 1GigE links where the value of RTT is greater than 0.