NFS Performance Tuning for HP-UX 11.0 and 11i Systems

nfs performance tuning for hp-ux 11.0 and 11i systems page 50

Notes:

Page 50July 22, 2002

nfsd

Can you change the NFS/TCP “single

connection” default behavior?

• The number of connections an NFS/TCP client establishes

to a server is defined by an undocumented kernel

parameter called “clnt_max_conns”

• The only way to change this parameter is via adb(1)

WARNING WARNING WARNING

Ø The following procedure is NOT SUPPORTED BY HP

Ø This procedure should be used with caution, as it will modify the

client’s behavior when mounting filesystems from any NFS/TCP

server, not just HP servers.

By default, HP-UX NFS/TCP clients only open a single connection to each NFS

server, regardless of how many NFS filesystems the client mounts from the server.

This behavior can be changed by modifying an undocumented kernel variable with

adb(1). This procedure is NOT SUPPORTED BY HP. Use at your own risk.

To force an HP-UX 11.0 or 11i client to open more than one NFS/TCP connection

to each server it mounts filesystems from, log into the client as a root user and type:

# echo “clnt_max_conns/W 0d2” | adb -w /stand/vmunix /dev/kmem

# echo “clnt_max_conns?W 0d2” | adb -w /stand/vmunix /dev/kmem

In the above example, the “0d2” parameter instructs the client to open 2

connections per server. The above commands modify both the on-disk kernel file

and kernel memory so the change takes effect immediately, and will remain in

effect even if the client system is rebooted. These commands would need to be

repeated if the kernel is rebuilt, either manually or via a kernel patch installation.

To return to the default behavior, use “0d1” in the above commands.