NFS Services Administrator's Guide

Troubleshooting NFS Services
Performance Tuning
Chapter 5188
Improving NFS Client Performance
❏ For files and directories that are mounted read-only and never
change, set the actimeo mount option to 120 or greater in the
/etc/fstab file on your NFS clients.
❏ If you see several “server not responding” messages within a few
minutes, try doubling the value of the timeo mount option in the
/etc/fstab file on your NFS clients.
❏ If you frequently see the following message when attempting access
to a soft-mounted directory,
NFS operation failed for server servername : Timed out
try increasing the value of the retrans mount option in the
/etc/fstab file on the NFS clients. Or, change the soft mount to an
interruptible hard mount, by specifying the hard and intr options
(the defaults).
❏ Enter the following command on the NFS server, to find out the block
size of the server’s filesystem:
/usr/sbin/tunefs -v devicefilename
On the NFS clients, set the wsize and rsize mount options to the
bsize value displayed by tunefs.
❏ On the NFS clients, look in the /etc/fstab file for “stepping-stone”
mounts (hierarchical mounts), as in the following example:
thyme:/usr /usr nfs defaults 0 0
basil:/usr/share /usr/share nfs defaults 0 0
sage:/usr/share/lib /usr/share/lib nfs defaults 0 0
Wherever possible, change these “stepping-stone” mounts so that
whole directories are mounted from a single NFS server.
Stepping-stone (hierarchical) mounts, like the one in the example
above, cause more NFS requests than mounts from a single server. In
the example, if a client wants access to something in
/usr/share/lib, a request must be sent to server thyme, then to
server basil, and finally to server sage.
For more information on the stepping-stone mounts, see “Changing
the Default Mount Options” on page 83.