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

nfs performance tuning for hp-ux 11.0 and 11i systems page 51

Notes:

Page 51July 22, 2002

nfsd

Can you change the default

maximum of 10 threads/connection?

• The maximum number of threads the server is allowed to

launch for each NFS/TCP connection is defined by an

undocumented kernel parameter called “maxthreads”

• 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

server’s behavior when servicing NFS/TCP mounts from any

NFS/TCP client, not just HP clients.

By default, HP-UX NFS/TCP servers launch a maximum of 10 kernel threads to

service requests for each NFS/TCP connection, regardless of how many NFS

filesystems the client accesses on 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 allow an HP-UX 11.0 or 11i server to launch more than 10 NFS/TCP threads

per connection, log into the server as a root user and type:

# echo “maxthreads/W 0d20” | adb -w /stand/vmunix /dev/kmem

# echo “maxthreads?W 0d20” | adb -w /stand/vmunix /dev/kmem

In the above example, the “0d20” parameter instructs the server to launch a

maximum of 20 threads per connection. These commands modify both the on-disk

kernel file and kernel memory so the change takes effect immediately, and remain

in effect even if the server system is rebooted. The adb commands must repeated if

the kernel is rebuilt, either manually or via a kernel patch installation. To return to

the default behavior, use “0d10” in the above commands.