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

nfs performance tuning for hp-ux 11.0 and 11i systems page 64

Notes:

Page 64July 22, 2002

rpc.lockd

rpc.statd

Ensuring Optimal NFS File Locking

Performance

• Verify that hostname resolution servers (i.e. DNS,

NIS, etc.) are responding and return accurate data

• Remove obsolete files from /var/statmon/sm.bak

to avoid forcing rpc.statd to continuously try contacting

systems which no longer exist in the environment

Even when NFS file locking is functionally working, hostname resolution still plays a

key role in rpc.lockd and rpc.statd performance. There are several places in the

lockd and statd source code where the gethostbyname() routine is called to retrieve

the IP address of the remote system. Therefore, if hostname resolution performance

is poor then NFS file locking performance will suffer as a result. Again, this could

involve DNS, NIS, NIS+, or the /etc/hosts file – depending upon how

hostname resolution is configured in the /etc/nsswitch.conf file.

During NFS lock recovery, if statd is unable to notify a system associated with a

/var/statmon/sm.bak file then this file remains in the “sm.bak” directory.

Statd will continuously attempt to notify this remote host every 15 seconds. If statd

is busy trying to contact these non-existent or dead clients it will either be unable to

handle new monitor requests for legitimate NFS clients, or it will take a long time to

process these requests. In either case, file lock performance can suffer. It is

therefore important to periodically monitor the contents of the “sm.bak” directory.

If files associated with obsolete clients are found then they should be removed

during the next scheduled maintenance window.