Unmounting a failed NFS mount

UNIX AIX
1

I have an NFS file system mounted on one of my AIX servers with "mount -v cifs".. The server from which the file system was mounted has crashed and now my "df -g" output is hanging. Is there any was to unmount this NFS file system? I have tried "umount -f". Doesn't work.

Or is there any way in which I can make "df" command to not search for this file system and skip it?

---------- Post updated at 02:14 PM ---------- Previous update was at 02:12 PM ----------

I want to add that is there something like the /etc/mtab file on AIX to disable df reading the file system?

2

There is "/etc/filesystems" and the ODM. Which information exactly do you look for or was this a general question?

I hope this helps.

bakunin

3

This question is related to the unmount issue. In Linux there is a file /etc/mtab. If you remove the entry of a file system from this file, the file system will not be displayed in the df output. So I wanted to know is there any similar way in AIX to disable reading/scanning of a file system by df?

The main issue here is how to unmount the NFS file system when the host server has crashed?

Thanks.

4

Actually "df" is not really hanging: the real problem is that NFS has - because of historical reasons - extremely long timeouts (IIRC 20 min or so). I suppose that, given enough time, "df" would finally come to a regular end.

About your question: no, you can't exclude any mounted file system from "df"s output, at least not to my knowledge.

I hope this helps.

bakunin

5

Ok. So there is no way to exclude a file system from DF output. But is there any way for us to unmount a failed NFS mount without requiring a reboot? Also we have 2 systems where we are facing this issue. umount -f worked on one and gives and error on the second one:

"There was an error with unmount".

6

Have you tried shutting down the underlying protocols? Maybe a stopsrc -g nfs might help?

In general i wouldn't let my environment depend on NFS at all, probably you'd be better off replacing NFS with something more robust (like a SAN share or something such?). NFS is IMHO ok for some temporary mount - mount an installation directory for an update, etc. - but not for production purposes.

I hope this helps.

bakunin

7

If your nfs share is automounted, stop the automounter, than umount -f

To avoid such a situation in future, choose the correct mountoptions in future for nfs mounts, like small retry number, short interval, soft instead of hard mount and similar things.

Regards
zxmaus