Hi all,
This is a very late summary, but I only recently got back from holidays
so better late than never :). My original question (see below) was how
to unmount an NFS mount when it would not unmount by using the umount
command and the ip address of the NFS server has changed, without having
to reboot the client. Various suggestions were made, they are;
1. Reboot the machine (this will be the cleanest method of clearing the
NFS mount and many said that on occasions the only solution).
2. On another machine give it the same hostname and ip address of the
original NFS server and set up the same NFS shares and try and umount
the NFS mount. (This would have been an interesting experiment but I
could not afford the time to do this but replies indicated that this has
at times worked for people)
3. Use "fuser -c <mount-point>" to find out what proccesses are running
on the NFS mount, kill those processes and retry the umount command. In
addition just lsof to find open files on the filesystem.
4. Restart the nfs daemons on both client and server machine and retry
the umount command.
5. Try using the lockfs command to force an umount.
Thanks to all those who replied, it was very much appreciated,
unfortunately in the end I did have to reboot and that fixed the
problem. FYI before the reboot I did try restarting all the nfs-related
daemons on the nfs client only (was not possible to restart the nfs
daemons on the nfs server), this did not do a thing. Editing the
/etc/mnttab file helped clear the hang on a "df -k" command but did not
make any difference to umounting the nfs mount.
If anyone would like the replies I received please email me and I will
email you back with them.
__________________________________________________________________________
original question:
> I have an NFS problem which I urgently need a resolution on. Our Sun
> machines are NFS clients to a NFS server (non Sun platform) which
> recently got moved to a new machine. Hence the ip and the host name of
> the NFS server has changed. Unfortunately I did not unmount the NFS
> mounts on our Suns before they moved the NFS service over to the new
> box.
>
> Now I cannot unmount the NFS mount points which is still trying to talk
> to the non-existent old NFS server. When I try to unmount the NFS
> mounts the prompt just hangs and I get the NFS server not responding
> warnings. I have read all the newsgroup items on NFS stale file handles
> and so forth and all seem to point to the only resolution is to reboot
> the NFS client machines. But this is something I want to avoid as these
> Sun machines are production machines.
>
> I have tried editing the hosts file to point to the new ip address but
> when I do and try to umount the NFS mount it tells me that the NFS mount
> is busy. Using the "fuser" command does not come back with any results.
> The NFS mount is hard mounted. Sun Support suggested bringing up the
> old nfs service for a few minutes so I could try unmounting then but
> unfortunately that is not possible in my case.
>
> Question 1:
>
> Has anyone had this problem before and how did you resolve it?
>
> Question 2:
>
> What exactly is happening when you issue a umount command on a NFS
> mount, does it need to establish a "link" with the NFS server for it to
> release the NFS mount??? What is it trying to look for??
>
> Question 3:
>
> What would happen if I stop the following nfs related daemons and then
> restarted them?
>
> /usr/lib/nfs/statd
> /usr/lib/nfs/lockd
> /usr/lib/nfs/nfsd
> /usr/lib/nfs/mountd
>
> Would that have any fatal consequences, ie would it hang the machine,
> would that totally screw up any new nfs mounts I try to make?
>
> Question 4:
>
> Would editing the /etc/mnttab (ie take out the nfs entry) and then
> restarting the nfs daemons be worthwhile or am I getting myself into
> more trouble?
>
> I would appreciate any comments or advice and thank you very much for
> any help you can offer me.
>
Nellie Lee
This archive was generated by hypermail 2.1.2 : Fri Sep 28 2001 - 23:13:28 CDT