NFS Gateway for NetWare 6.5 has the ability to dynamically tune certain parameters to help ensure successful communication.
The RPC timeout (-rpcTimeout parameter on GYMOUNT) value is dynamically adjusted based on network conditions. NFS Gateway will not adjust this setting below that which the administrator sets, but it will adjust it higher when round-trip communication between NetWare and the remote UNIX or Linux system shows a pattern of taking more time. This feature is enabled by default, but can be turned off with the GYMOUNT -noDynamicRPCTimeout parameter.
Dynamic tuning of Max Outstanding Packets (-maxOutstandingPackets parameter of GYMOUNT) is also available, although it is not enabled by default.
The default -maxOutstandingPackets setting (8) is already somewhat conservative, but if network timeouts are experienced while doing reads or writes on an NFS Gateway volume, enabling the dynamic tuning (-dynamicMOP) will significantly eliminate risk of those timeouts.
Rather than requiring the administrator to permanently lower the -maxOutstandingPackets setting, the dynamic tuning can lower that setting on-the-fly, and then raise it afterwards as the trend of successful communication builds. With this feature enabled, when a retransmission becomes necessary, NFS Gateway will lower the setting by 50% in order to reduce load on the LAN or remote server. Potentially, if more than one retransmission are occuring, this feature can adjust -maxOutstandingPackets from the administrative setting (default 8) down to 1. It will adjust back up quickly during periods of successful communication. This feature is disabled by default.
NOTE:When using -dynamicMOP, some fluctuations in performance might be noted, as the system adjusts the rate at which it is sending requests to the remote system.
To see a snap shot of the level these dynamic parameters have reached, give the following system console command and check the logger screen for output.
gymount -d -volparams [volumename]
This displays the current dynamically reached parameter values rather than the administrative setting.For tuning other parameters, or if you feel it is necessary to manually tune -rpcTimeout or -maxOutstandingPackets, the other sections of this chapter gives tips and suggestions.