NFS Mounts Even Though Automounter Is Turned Off

[Mark Duffy]

I have a couple of servers here which have an NFS mount to an NT server. Automounter is turned off and nfsconf also has the automount option set to 0 (off).

Lately, the NT server has been crashing. Once backup, the NFS partitions on the HP servers automatically remount without any manual intervention. Could anyone explain how this could happen. What is telling the server to re-read fstab and re-mount once the NT server comes back online?

Cheers,

Mark

[Santosh Nair_1]

This is the way NFS works. When a machine boots up, it tries to mount all the filesystems in /etc/fstab, both local and NFS. So after the crash and subsequent reboot, the NT machine mounts all the entries in the fstab file just like its supposed to. This has nothing to do with automount.

If you don't want the filesystems mounted on reboot, then you can specify the noauto option in the fstab file (implementation varies on the OS). You would have to refer to your documention for the mount command for more details on how this can be done.

Hope this helps.

-Santosh

[Mark Duffy]

Santosh,

Thanks for the quick response. It's the NT server that is rebooting and not my HPUX one.

I know if the HPUX server rebooted then it would read fstab again and remount everything but it hasn't crashed so why does it remount the NFS partition once the NT server has come back online?

[Mark Duffy]

I've realised I've badly worded my original question.

The HP server hosts an NFS mount FROM the NT server and not to as I mistakenly wrote.

[Santosh Nair_1 · Accepted solution]

Okay, I'm a little confused...are you mounting from the NT onto the HP machine or the other way around? If its the former, then when the NT machine reboots, the HP machine doesn't unmount the NFS filesystem...they just become non-responsive. Once the NFS server, i.e. the NT machine, comes back up, the HP machine is able to "re-establish" the NFS mount. Since NFS is stateless, if nothing is happening between the time the NT machine crashes and its subsequent reboot, then you won't see any errors...otherwise you should see some "NFS server not responding" errors.

Hope this helps.

-Santosh

[Mark Duffy]

I'm mounting from the NT onto the HP machine. I realise now that because the partition wasn't actaully 'umounted' but 'unavailable' then when the NT server starts up NFS again the partition doesn't actaully 're-mount' but just becomes 'available' again.

Thanks for the help.

[Krishna Prasad]

Because the mount was already established NFS will go to a stale mount state while the NT Server is rebooting. The NFS client will try to remount the NFS mount point until it times out. If you are lucky and the NT server is back up fast enough it will remount without any problems. If it is down for longer period of time....I have seen the NFS client give up and not be able to re-mount the NFS volume until a reboot.

So...In a way you are lucky that it is coming back quickly....but it is how the NFS client works.

[Sanjay_6]

Hi Mark,

Another thing worth checking is the mount options in your /etc/fstab file on ux server. If you are using a "retry" option with this filesystem, the system will keep on trying to mount a NFS filesystem in the background even if it is unable to mount the filesystem in its first attempt.

What you said about the filesystem becoming unavailable and then again becoming available could also be the correct reason for the system being able to access the NT filesystem again.

Hope this helps.

Regds