Automount

Robert Meyer meyer_rm at yahoo.com
Thu Oct 25 08:52:29 EDT 2001


Yes, every filesystem will balk at being unmounted if it's in use in any way. 
It's not the disk cache that's doing it, it's the fact that it's still in use. 
Sitting in the directory, a program running in the directory or files open in
the file system all will cause the thing to not be unmountable.

Second question: Yes, this is for network filesystems, too.  Multiple systems
can mount any NFS directory from any server that lets them.  NFS is stateless
so writes are not cached but directly written immediately.  You still have the
situation that if the file system is in use, you can't unmount it.  You CAN
find out who is using a filesystem that you're trying to unmount with the
'fuser' command.  There's a bunch of options, including killing the processes
that have the file system open.

By the way, for floppies and CDROMs, I prefer 'supermount'.  The autofs default
timeout is something like five minutes but supermount unmounts the filesystem
as soon as it's not in use.  It was designed specifically for removable media.

I HAVE made autofs do very fast timeouts but I haven't experimented with it too
much.  For floppies, you can also use the 'mtools' package.  It provides means
to do most of the standard things that you'd want to do with the floppy.  It
provides commands like 'mcopy', 'mdel', 'mmkdir', 'mrmdir', etc.  The cool
thing is that mtools doesn't actually mount the floppy, it works on the raw
device.  Of course that means giving everyone access to the raw floppy device
:-)

Hope this helps...

Cheers!

Bob

--- "Wechter, Ron" <WechterR at cnrc.navy.mil> wrote:
> OK - I answered my own question.  I was getting confused on the floppy disk
> mount.  I noticed (I never have to copy data to floppy disks - I always used
> to working with everything over the network) that the /etc/fstab has a
> listing for "noauto" for /dev/fd0 -- This means for autofs to not automount
> AND (the biggest of them all) when I went to unmount the file system (floppy
> disk) it would not unmount.  Well my pwd was still /mnt/floppy/ and it would
> not unmount because the disk cache was still being used (I was in the dir) 
> 
> Long story short - I was not using common sense AND my inexperience with
> mounting floppy disks got the best of me.
> 
> ****Does this theory hold true for network files sytems too?  If a file is
> being used in the files sytem will linux be able to unmount it if needed?
> Can more than one computer mount the same files sytem (network resource?).  
> 
> Ron
> 
> -----Original Message-----
> From: Wechter, Ron [mailto:WechterR at cnrc.navy.mil]
> Sent: Wednesday, October 24, 2001 3:26 PM
> To: 'nflug at nflug.org'
> Subject: Automount
> 
> 
> Automount in Redhat 7.1
> 
> autofs is installed and the RPM query states that it will automagically
> mount and unmount file systems, including floppy drives.  Does this actually
> work?  The daemon is running but I still have to mount and unmount the
> /dev/fd0 everytime I put a floppy disk in there.  
> 
> Do I have to invoke something or should I do a rpm -e and did it the ol
> fashioned way?
> 
> Ron


=====
Bob Meyer
Knightwing Communications, Inc.
36 Cayuga Blvd
Depew, NY 14043
Phone: 716-308-8931 or 716-681-0076
Meyer_RM at Yahoo.com

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