Clients with home directories on NFS hanging on login

Question

I have several client machines running Ubuntu 10.04 that mount home directories from a central NFS server, also running Ubuntu 10.04. Users are authenticated through a central Windows AD using samba and winbind on the client machines.

Recently I get this behavior that when some users log in, the login screen hangs and never takes them to their desktop. If they log in from a terminal, it displays the welcome message, but hangs before their prompt comes up. The NFS mount is attached and active, as I can log in as a local user and ls it. The behavior looks like the client machine is trying to get a lock or read a file and there is no response from the NFS server.

I've looked through the logs and not seen any suspicious entries. I have purged the nfs server and client installations and reinstalled them. I have no idea what to do from here.

The client fstab looks like this:

csfile.stlawu.local:/home/stlawu /home/stlawu nfs rw,hard,intr,noatime,_netdev 0 0

While the server exportfs looks like this:

/usr/local/cs 10.32.95.0/255.255.255.0(rw,async,no_subtree_check,no_root_squash)

Any ideas on what I can do to debug/fix this problem?

Answer 1

I have seen this kind of behavior when a directory in the PATH is automounted nfs and that directory is unavailable or unresponsive.

I would check the PATH for those accounts. Make sure there is nothing automounted in the path. Then you can add directories one by one and find out which causes the hang.

Another possibility is that you may have some uid mismatch between your accounts from samba and your accounts on the nfs server. When you run 'ls -l' on a users nfs home directory, do you see the correct username? If not you will need to configure Samba to map the usernames to the uids that the nfs server is using.