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NFS umount failed :"device busy"

Rambo_1
Regular Advisor

NFS umount failed :"device busy"

I can't umount the NFS even if after I used the
#fuser -kcu /NFS_mount_point.

someone told me the only way to fix it is to reboot the server . is it true ?
I'm looking for another way to fix the NFS umount problme .can anyone tell me ?

Thanks & B.R
rambo
10 REPLIES
Rafael Casero
Regular Advisor

Re: NFS umount failed :"device busy"

Seems that someone is cd into the mount point, have you tried forcing the umount ?

umount -f
Warren_9
Honored Contributor

Re: NFS umount failed :"device busy"

Hi,

try the "lsof" and it may be able to locate the open file/process on the mount point.

http://hpux.cs.utah.edu/hppd/hpux/Sysadmin/lsof-4.77/

GOOD LUCK!

Warren
Andrew Young_2
Honored Contributor

Re: NFS umount failed :"device busy"

Hi Rambo

You will probably find that using lsof that it is opened by the kernel, this is the NFS daemon doing this. You may need to stop all the NFS daemons being NFS server, NFS client and NFS core in that order. If that doesn't work there is the option of restarting Rpcd however I would not do that unless you really are feeling brave as many other daemons use this too. Rebooting may be easier if it is an option.

HTH

Andrew Y
Si hoc legere scis, nimis eruditionis habes
Paul Senior_1
Frequent Advisor

Re: NFS umount failed :"device busy"

1)is this the nfs server or client (or both)?

2)is there any 3rd party s/w which uses nfs which needs to be stopped (e.g. file CIFS sharing s/w on another machine - e.g. a windows server

3) is it a hard nfs mount (is the nfs server up?)

4)very obvious, but worth stating: are you in the nfs mount directory or do you have a current telnet session open in it? whatabout on the console?
Richard Tesar
Occasional Visitor

Re: NFS umount failed :"device busy"

If you have mounted NFS volume from any NFS server and this one for any reason cannot be reachable
you may have some problem during unmounting that shared followed this message "Device is busy".
In this case have two choice. Wait for NFS server or disconnect by force. In principle is
concerned it oust of nfs lock. The trick is to send a SIGKILL to the 'lockd' kernel thread.
This tells lockd to release all of its locks.

good luck
rich
Dennis Handly
Acclaimed Contributor

Re: NFS umount failed :"device busy"

>rich: The trick is to send a SIGKILL to the 'lockd' kernel thread. This tells lockd to release all of its locks.

I can't comment whether this is true, no mentioned of special signals lockd(1m) handles. But one thing is certain, if you send SIGKILL, that processs can't do anything. And if you kill lockd, you must restart it manually.

Re: NFS umount failed :"device busy"

You could do a kill -HUP on the lockd process
Dennis Handly
Acclaimed Contributor

Re: NFS umount failed :"device busy"

>Timothy: You could do a kill -HUP on the lockd process

I doubt it. It isn't documented and the sources don't show this.
MSufiyan
Occasional Visitor

Re: NFS umount failed :"device busy"

or try to mount on temp dir

 

for eg: mount /NFS_mount_point /tmp/test_ms

If you get success , then

rmdir the original mount point

create it one more time

 

mkdir -m 755 mount_point ( the one you have removed )

umount /tmp/test_ms

mount /NFS_mount_point mount_point

Todd McDaniel_1
Honored Contributor

Re: NFS umount failed :"device busy"

Is this mount point defined in fstab or manual mount?

 

I have seen cases where you can blow away the mnttab and immediately attempt a umount. (and/or comment out the entry in fstab)

 

I'd suggest executing the umount command, which will fail. then rm mnttab, then arrow up and run umount again.

 

Regards,

 

Todd McDaniel

Unix, the other white meat.