# unmounting a busy NFS

## lutraman

I have a problem unmounting a dead NFS, with an error message: "umount.nfs: Server failed to unmount"

looking at existing threads at this subject I understand I need to run fuser to check what process keeps the mount busy.

however, fuser just seem to be running at the background without any output, until I give up and ^C. even fuser -V (to display the version) does the same. it's just stuck.

I'm thinking of installing lsof using emerge but I'm not sure it will do any better.

any advices on how to continue from here? keep in mind that a restart is out of the question (this is a phone operator with at least 50 active calls 24/7).

Thank you.

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## papahuhn

I would perform a lazy umount.

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## lutraman

I was looking into doing this before, but I'm afraid of system instability.

since I can't unmount it now, because of some process trying to access it, lazy umount will just wait forever.

I'm more interested in knowing why fuser just hangs. Also, I just installed lsof and as I suspected, it does the same, just hangs there until I ^C.

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## Hu

The hang is normal if the NFS server has gone away.  Bring back the NFS server and you should be able to unmount normally.

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## lutraman

I can't do that, the server hosting the NFS has already been formatted.

anyway, I couldn't wait anymore and failing to find another solution I took papahuhn advice and went for the lazy umount.

I do have a few questions though.

It seems strange that fuser will just hang. what if I want to check a file that is not related to the NFS. For example, I tried earlier to check if fuser -m /home also hangs, and it does. Why is that?

A more important question. Since I did the lazy umount, is there anything I should be wary of? Should I try to schedule a reboot anytime soon to avoid instability?

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## Jaglover

Did lazy umount succeed? If yes then you are good, no reboot needed.

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## syn0ptik

in what state nfsd?

may be it like that?

 *Quote:*   

> root     14495  0.0  0.0   8560   760 pts/15   D+   Mar08   0:00 mount -o loop 

 

I've sometime trouble with local loop's mount.

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