[CentOS] NFS issue, C7

Actually, with C6, too. We've been fighting a problem with a server with a
RAID appliance that's having issues. It's also serving /home/* and project
directories for one team. What happens is when the issues happen, NFS on
the other servers they use, of course, gags with timeouts.

Now, my question is this: if we go to reboot one of the other servers
where one or more home directories is being exported to, and is mounted by
autofs, it hangs, and will *not* reboot, because it can't let go of the
NFS-mounted directory, with the result that we have to physically go into
the room and power cycle the box.

Is there any way to configure NFS such that if a system is going down, NFS
will wait a few minutes while it retries, then time out and let it reboot?

      mark