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

nfs performance tuning for hp-ux 11.0 and 11i systems page 93

Notes:

Page 93July 22, 2002

Can you disable READDIRPLUS on an

HP-UX 11.0 or 11i NFS Server?

• The NFS server-side READDIRPLUS procedure can be

disabled by modifying an undocumented kernel

parameter called “do_readdirplus”

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

nfs pv2

vs.

nfs pv3

WARNING WARNING WARNING

Ø The following procedure is NOT SUPPORTED BY HP

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

READDIRPLUS operation on the server globally, thus impacting any

PV3 client – not just HP clients.

It is important to understand that after using the procedure described below, the

11.0/11i server will respond to any inbound READDIRPLUS request with an error –

NFS3ERR_NOTSUPP (operation is not supported). This causes PV3 clients to fall

back to the old PV2 method of READDIR/LOOKUP for obtaining directory contents.

This procedure is NOT SUPPORTED BY HP. Use at your own risk.

To disable READDIRPLUS on an HP-UX 11.0 or 11i server, log into the server as a

root user and type:

# echo “do_readdirplus/W 0d0” | adb -w /stand/vmunix /dev/kmem

# echo “do_readdirplus?W 0d0” | adb -w /stand/vmunix /dev/kmem

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 server system

is rebooted. These commands would need to be repeated if the kernel is rebuilt,

either manually or via a kernel patch installation. To re-enable READDIRPLUS

support on the NFS server, substitute “0d1” in place of “0d0” in the above

commands.