topic Re: mounting a file system in Operating System - HP-UX

mounting a file system

Shivkumar — Tue, 17 Jan 2006 14:19:50 GMT

can we unmount a file system without going into single user mode ?

Re: mounting a file system

Jeff_Traigle — Tue, 17 Jan 2006 14:21:28 GMT

Of course... as long as no process has a file open on the file system.

Re: mounting a file system

DCE — Tue, 17 Jan 2006 14:28:06 GMT

Yes you can, as long as there are no open files in the mount point. If it will not unmount (file system busy error message) you can use fuser or lsof to determine which processes have the open files, and either stop or kill them.

Re: mounting a file system

James R. Ferguson — Tue, 17 Jan 2006 14:29:14 GMT

Hi Shiv:

Yes. Make sure that you have not 'cd'-ed into the directory (mountpoint) that you are trying to unmount. If you have, you will be denied the action for "device busy".

You can use 'fuser' to see and optionally kill processes with open files in the directory hosting the mount.

Of course, you should *gracefully* stop all processes whenever possible! Running normal shutdown scripts is appropriate. For instanace:

# fuser -ku /dev/dsk/cXtYdZ
# fuser -ku /mountpoint

...sends a 'kill -9' to every process running with inuse files in the directory. This is *not* a nice thing to do. A 'kill -9' doesn't allow any cleanup of temporary files and/or shared memory segments to be made by the killed process.

Regards!

...JRF...

Re: mounting a file system

Pete Randall — Tue, 17 Jan 2006 14:30:31 GMT

Some file systems are simply *always* in use. That's when you need to go into single user mode to work on them. The rest, as long as no one is accessing them (either has a file open or is cd'd into them) can be unmounted without problem.

Pete

Re: mounting a file system

Geoff Wild — Tue, 17 Jan 2006 14:41:57 GMT

fuser -cu /mountpoint

to see what processes are using it.

Then you can decide what they are before you attempt to kill them.

Example - you won't be able to unmount / and /tmp and /var and /usr

Rgds...Geoff

Re: mounting a file system

Raj D. — Tue, 17 Jan 2006 18:03:00 GMT

Sure , if there is no file open we can unmount it.

1. Check if any file open for that FS.
# fuser -cu /FS_NAME

2. If nothing is there you can simply unmount it with umount command.

Else use # fuser -ku /FS_NAME to kill the processes if required.

And then use umount.

You cannot unmount /(root) , /stand , /usr , /opt , /var , as this are using system files/libraries, on multiuser mode.

Cheers,
Raj.

Re: mounting a file system

Indrajit_1 — Tue, 17 Jan 2006 19:55:50 GMT

Hi;
Yes u can do it until and unless it is not a root file system
Do the following steps

#bdf |grep -i
#fuser -cu

for example.. (fuser -cu /export/home)
if any body has logged in, cann't unmount the filesystem.. so

#fuser -ku
(i.e fuser -ku /export/home)
#umount /export/home

Hope it will help u to resolve ur issue..

cheers
indrajit

Re: mounting a file system

Hoang Chi Cong_1 — Tue, 17 Jan 2006 21:06:24 GMT

Yes! You can do it if there isn't any open file in that filesystem or any process access in!
To check for this, use "fuser -cu /filesystem" and you can see all of processes.
To kill them, use "fuser -kcu /filesystem"
Then you can umount it!

Remember: some filesystems call "sensitive" that if you try to unmout it, your system or application may get trouble because there are some system's process are runing on like /var, /opt, /usr....

Goodluck
Hoang Chi Cong

Re: mounting a file system

Shameer.V.A — Tue, 17 Jan 2006 22:26:59 GMT

Hi Shiv,

Yes you can unmount a filesystem, if it i snot being used by any application.

You should not be within the filesystem, otherwise it will give device busy error.

You can check for any open file through fuser command

You can't unmount system filesystem like /, opt, /usr.

Regards,

Shameer

Re: mounting a file system

Arunvijai_4 — Tue, 17 Jan 2006 22:37:23 GMT

Hi Shiv,

Two things to ensure before unmounting any FS.

1) Don't be in that FS any more. "cd" to any other directories.

2) Shutdown or kill all the processes using that particular FS.

Useful commands,
# fuser -u will list the processes using

# fuser -ku will clean up

-Arun

Re: mounting a file system

Yogeeraj_1 — Tue, 17 Jan 2006 23:25:19 GMT

hi,

also if you are unmounting it for good, don't forget to update your fstab file.

kind regards
yogeeraj

Re: mounting a file system

Sivakumar TS — Wed, 18 Jan 2006 00:23:29 GMT

Hi,

It is quite OK to unmount a filesystem as long as it is not in USE. NO NEED to enter in to single user mode.

If you want to kill all the process which uses the particular filesystem,

#fuser -ku

With REgards,

Siva.

Re: mounting a file system

Devender Khatana — Wed, 18 Jan 2006 00:31:27 GMT

Hi Shiv,

Was not it about a OS filesystem like /var , /usr etc?

If yes, then ofcourse you will have to boot to single user mode where by default these file systems will notbe mounted and you can perform some offline activities like extending etc.

For a normal file system like some non OS file system in vg00 or any file system in some other vg, unless the file systems is inuse by any process, you can very well unmount it.

HTH,
Devender

Re: mounting a file system

Arunvijai_4 — Wed, 18 Jan 2006 00:39:40 GMT

Hi Shiv,

Ofcourse, you can unmount /var, /usr, /opt when you logged in multi user mode.

http://docs.hp.com/en/B2355-90672/ch04s07.html

-Arun

Re: mounting a file system

Raj D. — Wed, 18 Jan 2006 13:13:40 GMT

Arun,
Just wondering if anyone has unmounted /usr filesytem in a running system.

If yes , what is the procedure , however there no much details in the document.

hth,
Raj.

Re: mounting a file system

Jeff_Traigle — Wed, 18 Jan 2006 13:23:45 GMT

You can't umount /usr in multi-user mode. (Well, technically, I guess you could if you stopped all of the daemons that get started that have /usr as their home file system... but, if you go to that trouble, you might as well go to single-user in the first place. :)

Re: mounting a file system

Steven E. Protter — Wed, 18 Jan 2006 13:31:07 GMT

Shalom,

if you have done this:

mount /cdrom

cd /cdrom

# launched a process like the Oracle installer.

There is NO way to umount the cdrom until that process has been killed.

fuser -cuk /cdrom

That will kill the processes, perhaps the system(though the later is very unlikely) and then you should be able to umount the cdrom

SEP

Re: mounting a file system

Raj D. — Wed, 18 Jan 2006 14:31:01 GMT

Unmounting system specific filesystems like /usr and /opt , seems cannot be done on multiuser mode. Even if we use fuser -ku or anyother trick.

hth,
Raj.

Re: mounting a file system

Devender Khatana — Thu, 19 Jan 2006 01:50:57 GMT

Hi,

One can not unmount /opt, /tmp, /var etc. file systems in multiuser mode inspite of closing all the applications. Reason being that the various processes started during bootup are still running and have files open in these file systems.

The link mentioned above nowhere states that you can unmount these file systems.

HTH,
Devender