NFS mounting blocked problems

Here is a new problem that can occur when mounting a filesystem over NFS: the name of the mount is too long. We got the following error trying to mount a disk called western_digital. One computer had no trouble mounting it, but the other got blocked:
conifer mountd[19916]: NFS mount of /western_digital attempted from 63.127.146.196
conifer mountd[19916]: NFS client host1.my_domain_name.com tried to access /western_digital
conifer mountd[19916]: Blocked attempt of 63.127.146.196 to mount /western_digital
conifer mountd[19916]: NFS mount of /western_digital attempted from 63.127.146.196

Changing the name to wd solved the problem:
conifer mountd[19916]: NFS mount of /wd attempted from 63.127.146.196
conifer mountd[19916]: /wd has been mounted by 63.127.146.196

Background

To export a disk, you do the following:

1. Add a line to /etc/exports like this (see man exports for details): /wd *.my_domain_name.com(rw,no_root_squash)
2. Find the process of rpc.nfsd and rpc.mountd: ps aux | grep mount; ps aux | grep nfsd
3. Send them a SIGHUP to get them to re-read the exports file. kill -1 12345; kill -1 12346
4. Then you should be able to mount them over NFS--unless your computer doesn't like the name.

On the server, if it's an external disk (such as a USB disk), don't add it to /etc/fstab. This would cause it to be mounted automatically at boot-up. If you later tried to boot the computer with this disk missing, the server would hang. Always mount external disks manually. If you forget, not to worry: your users will remind you within a few seconds (they're good about things like that).

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