Wednesday, August 08, 2012

NFS Mount Issue

I recently had a number of AIX server backups miss due to the backup hanging when doing its initial filesystem listing. At some point within the last day the mount's source was rebooted and all the mount points went bad. The problem is that TSM sits there trying to query it even though the default action is to not backup NFS mount points. So I had to log into each server, umount -f the file system, remount it, and then TSM was able to run successfully. TSM does not allow a DOMAIN -ALL-NFS so no matter what I do TSM is going to hang on the listing of file systems. Of course doing a df on the server hangs also, so it's not just a TSM issue. Anyone else ran across this issue?


  1. Are your NFS mounts hardmounted? With hardmounted NFS filesystems in which the filesystem becomes unavailable, the client will continue to try to connect until the filesystem is once again available. The would explain why df hangs as well as the backups. With softmounted NFS filesystems, an error will be returned and the client continues. With AIX, the default is hardmounted. Whenever I create an NFS filesystem in AIX I always change this to softmount unless I have a compelling reason to leave it hardmounted.

  2. Yeah they hard mounted the file systems. Not sure why. I'll have to have the UNIX admins change the settings in the fstab.

  3. Also, be aware of this issue IC81218

    It happens in more situations than the ones described. This bit me when NFS was unavailable at the beginning of the backup, causing it to hang. Then when it became available, the backup continued, but backed up the NFS mount as if it was local to the parent file system.