Q:  Why is the performance of my file server so poor?  The load is high and rpc.mountd is taking up large chunks of CPU time.

A:  There is a file called /etc/rmtab, which contains statistics about remotes mounts.  See the man page rmtab(5) for details.  When an NFS client crashes, it does not remove its entry in this file and so as more NFS clients crash, the file /etc/rmtab on the file server grows without bound. Eventually things break or slow down severely.  Notable symptoms are:

	The file /etc/rmtab is large--there should only be one line for each NFS client mounting a file system.
	High %CPU (e.g., higher than any other process) value as shown by ps -aux:

nfsserver% ps -aux | grep mount
USER       PID  %CPU %MEM VSIZE RSIZE TT STAT  TIME COMMAND
root       276  19.6  1.4 1.23M  224K ?  S     0:00 rpc.mountd

...

	High load values on the server immediately following multiuser boot.
	Home directories not mounting properly.

The fix is as follows:

1)	Boot the machine in single-user mode.
2)	Empty the file /etc/rmtab (e.g., cat /dev/null > /etc/rmtab).
3)	Reboot.

This solves the problem.

QA565

Valid for 1.0, 2.0,3.0,3.1