11.31 - cannot umount even if no processes are on mnt point

[DuKul]

Hello all,

I am facing strange problem. I cannot umount filesystem even if there are no processes on it.

While switching the related package, the MC/SG could not umount the FS because there have been some (SAP) processes there. (This FS had been NFS-exported onto another node before, but it had been umounted there.)

I have checked the processes there (fuser -cu) and there have been none so I have tried to umount it afterwards but to my surprise this could not be done:

umount: cannot unmount /dev/vgNSParch/lvsapmnt : Device busy
umount: return error 1.

I have checked open files:

(root)#/usr/local/bin/lsof | grep NSP
ksh 48030 root cwd DIR 64,0x4 96 3099 /etc/cmcluster/NSP
timeoutmo 54044 root cwd DIR 64,0x20002 1024 2 /sapmnt/NSP
time_out 54049 root cwd DIR 64,0x20002 1024 2 /sapmnt/NSP

(root)#ps -ef | grep -E '54044|54049'
root 54049 54044 0 19:28:44 pts/1 0:00 /opt/hpsmh/lbin/time_out /opt/hpsmh/logs/smh.timestamp 30
root 54460 51220 0 19:37:59 pts/1 0:00 grep -E 54044|54049
root 54044 1 0 19:28:44 pts/1 0:00 /usr/bin/sh /opt/hpsmh/lbin/timeoutmonitor 30

(root)#kill 54049 54044

(root)#umount /sapmnt/NSP
umount: cannot unmount /dev/vgNSParch/lvsapmnt : Device busy
umount: return error 1.

I have started the package again and tried to umount the FS - still the same.

I have even tried this dirty way:

# cp -p /etc/mnttab /etc/mnttab.bak
# rm /etc/mnttab && umount /sapmnt/NSP

...still the same (sighing desperately).

Could you help me anybody?

Dusan

[Jeeshan]

Hi

issue command to send SIGHKILL to open files in that mount point

#fuser -ku /sapmnt/NSP

or see which file is accessing yet

#fuser -cu /sapmnt/NSP

[Jeeshan]

then unmount the file system

[DuKul]

Ahsan,

please read all of my post before posting something.

As stated in the original post, I have done all the magic with fuser but with no positive results - and this is indeed one of the points.

Dukul

[Jeeshan]

sometimes fuser didn't recognize if any user or any processes still accessing if there any direcory beneath the /sapmnt/NSP file system.

you may be then check whole system ps -ef output

[vladimir drzik_1 · Accepted solution]

Hi Dusan,

Maybe kernel is still holding this filesystem opened. If it was exported via NFS. Have you used HA NFS?
showmount -e is showing something?

Regards,
Vlado

[DuKul]

Hi Vlado,

great!
I have totally forgotten to check this.

So this was indeed the root cause:

(root)#showmount -e
export list for mcsapprd:
/sapmnt/NSP (everyone)

The rest was easy:

(root)#/sbin/init.d/nfs.client stop
killing nfs4cbd
(root)#/sbin/init.d/nfs.server stop
killing nfsd
killing rpc.mountd
(root)#/sbin/init.d/nfs.core stop
killing nfsmapid
killing rpcbind
(root)#umount /sapmnt/NSP
(root)#

UMOUNTED !:-)

Thanks for teaching me that the most simple approach works the best :-)

Dusan

[DuKul]

Occam's razor in praxis :-)
The most simple check led to solution.

[Dennis Handly]

If your solution didn't work, on 11.31 there is a umount -f option to force it to be unmounted.

[zonfeng]

in 11.31 NFS,you need first type:unshare /sharepoint ,then use umount /sharepoint, I test it ok.