Input / Output Errors on NFS Clients

Hi all,

Twice in the past month, we've been getting input/output errors on at least two of our NFS client boxes.

We have a single NFS server with two directories exported. Each NFS client mounts the directories which serve as the /home/users directory on the local box as well as flat file storage.

This only started happening back on the 14th of this month (first occurrence), and happened again today on a different client box. When this issue occurs, none of the other client machines experience the same problem, making me believe that it's not the NFS server itself.

I don't see any NFS errors on the client in /var/log/messages, and I don't see anything NFS related in the logs on the server. The only tell for this is that when trying to use the mounted directories, the users get messages stating "Input / Output Error."

Rebooting the client box fixes the issue, but doing so is problematic for the client, and not a welcomed solution. I'm relatively new to Linux administration- does anyone have any suggestions for how to retroactively find out what's happening?

I've done some research, and it seems the best way to diagnose these problems is during the occurrence, so I'm thinking I'll just wait for it to happen again and run some diagnostics during the outage. But if anyone knows how I can find out what may be causing this, I'd be highly appreciative.