Managing NFS and KRPC Kernel Configurations in HP-UX 11i v3 (762807-001, March 2014)

In most situations, this single connection paradigm works well. However, in certain cases the client
can perform better if more than one TCP connection is used to communicate with the NFS server.
Tested Values
Default: 1
Min: 1
Max: 10
Note: If the tunable is set to a value greater than 10
connections, an informational warning is issued, at runtime.
Any value greater than 10 is beyond the tested limit.
Restrictions on Changing
The rpc_clnt_max_conns tunable is dynamic. System reboot is not required to activate changes made
to the value of this tunable.
Modifying the Value
In most cases, a single TCP connection adequately handles the load of a single client, even for
multiple filesystems mounted from the same server. In some cases, the client can benefit from opening
multiple TCP connections to the NFS server. For example, if both the client and the server are using a
4-port APA trunk and mount filesystems across the APA trunk, they experience better performance and
overall throughput if the rpc_clnt_max_conns tunable is increased to 4, thus matching the number of
physical ports in the APA trunk.
2.3.3 rpc_clnt_udpresvports
Description
The rpc_clnt_udpresvports tunable controls the number of UDP reserved ports that the KRPC subsystem
makes available for use by other processes. By default, the KRPC subsystem is allowed to consume all
UDP reserved ports on the system. By setting the rpc_clnt_udpresvports tunable to a non-zero value,
you are specifying the number of UDP reserved ports that are “off limits” from the KRPC subsystem,
thus allowing other applications to use these ports.
Tested Values
Default: 0 (KRPC subsystem is allowed to consume all UDP reserved ports)
Min: 0
Max: 256
Restrictions on Changing
The rpc_clnt_udpresvports tunable is dynamic. System reboot is not required to activate changes
made to the value of this tunable.
Modifying the Value
In general, the default value of this tunable allows the KRPC subsystem and other processes to
concurrently share the UDP reserved port space. However, under certain workloads, an application
may not be able to obtain a reserved port because KRPC has consumed too large a percentage of the
pool of reserved ports. In extreme cases a “bindresvport” error will be logged to syslog when the pool