SUMMARY: cannot unmount cdrom

From: Sahir Siddiqui (
Date: Thu May 09 1996 - 09:47:22 CDT

Thanks to all the people who responded. Unfortunately there was no
answer I could use.

My original question was:

> Sun 690MP - SunOS 4.1.3_U1.
> I'm having trouble unmounting the cdrom. The cdrom is on device
> /dev/sr0, and I have a softlink /dev/cdrom pointing to it.
> menger# ls -l /dev/cdrom
> lrwxrwxrwx 1 root 8 Feb 14 17:30 /dev/cdrom -> /dev/sr0
> menger# ls -l /dev/sr0
> br-xr-xr-x 1 root 18, 0 Aug 19 1992 /dev/sr0
> Its mounted on /cdrom -
> menger# mount -t hsfs -o ro /dev/cdrom /cdrom
> menger# mount
> ...
> /dev/cdrom on /cdrom type hsfs (ro)
> ...
> Unmounting it is impossible!
> menger# umount /cdrom
> menger# umount /cdrom
> /cdrom: Device busy
> I used 'lsof' to determine that nobody is holding the directory open.
> I'm not in that directory either. I just cannot unmount it.
> A peculiarity, however:
> menger# umount /dev/cdrom
> /cdrom: Device busy
> menger# umount /dev/sr0
> mount: /dev/sr0 not mounted
> Can anyone explain how to unmount it? What are the repurcussions of a
> manual eject of the cdrom?
> -s

As I explained above, I used 'lsof' to check that nobody was accessing
the device. 'fuser' also reported the same thing.
One admin reported that the problem stopped appearing on upgrading to
SunOS 4.1.4.
I finally had to resort to a shutdown/reboot of the system.

The responses I received are below.

From: George Goffe <>
Subject: Re: Cannot umount CDROM

Hi there,
I've seen this too. Solaris systems have a vol daemon and there's some
automounting being done, blah blah blah...
I have used filemgr to accomplish this in the past. I have, however,
had some experiences where a shutdown/manual eject/boot was the only
Good luck,
From: Venkata Ramakrishna R <>
Subject: Re: Cannot umount CDROM

Hi Sahir,

 Definetely some one must be using it.

 Check if it is remotely mounted on to some other machines.
 Check if any processes are using /cdrom using "fuser" command.

From: Olga Aronov <>
Subject: Re: Cannot umount CDROM

I was having the same problem on SS20 and Sun)s 4.1.3_U1

I never worked out how to unmount it.
Neither did my more experiewnced collegues.

The only way to free a cdrom was reboot.

When I forced a cd to eject the machine would panic and reboot
in a few hours after that.

I called SUN Support about this problem but didn't get any solutions.
In facy they said they didn't know the problem existed.
Apparantely it does ;)

In the end I upgraded the machine to 4.1.4 and installed
patch 102583 (hsfs JUMBO PATCH).

THe reason I upgraded to 4.1.4 was because I couldn't find
similar patch for 4.1.3_U1 plus we were bringing all the machines
to 4.1.4 anyway.

The upgrade was about 6 months ago and we didn't have a single
problem with this cdrom since.

From: Stephen Harris <>
Subject: Re: Cannot umount CDROM

Hmm. Did you do a level 0 backup of / while the CD was mounted? Back
when I had to admin a 4.1.3 system that was guaranteed to permanently
"busy" the CDROM requiring a reboot.

> Can anyone explain how to unmount it? What are the repurcussions of a
> manual eject of the cdrom?

When I tried it.... kernel panic! :-)

From: Fedor Gnuchev <>
Subject: Re: Cannot umount CDROM

a couple of simple checks:
1 - you cannot umount fs which holds your current dir
so try cd / ; umount /cdrom
2 - if a user on your system cd'ed to /cdrom/somewhere - he can prevent
you from umounting it

Eh, these is just a wild guess, but that what I'd seen when people
complained that they cannot eject CD with "eject CD" function in filemgr
- they thought that it was their private resource while several other users
where actively searching that very CD.

With best regards

Fedor Gnuchev

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