On Tue, Mar 5, 2013 at 3:24 PM, <jboyce@meridianenv.com> wrote:
Greetings -

Ok, I made a mistake that I need to fix.  Fortunately it is not a
destructive mistake, but I need some advice on how to correct the problem.

CentOS 6.3 host system named Earth

I was creating some new logical volumes within my exiting volume group for
a new virtual machine using the LVM GUI.  When I created the LV that I
plan to use for root partition of the new VM (Bacteria) I mistakenly
clicked on the box to mount the LV, and specified the mount point as /.


So you mounted that new LV as / (or over the existing root) on your host node?

You may end up needing to boot to a rescue CD, mount, and rsync files from Bacteria's root to Earth's [real] root.  ( I wonder if anything is being written to Bacteria's root since it's mounted over the real root. )
 
[root@earth ~]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/vg_mei-lv_earthroot
                      5.0G  3.9G  880M  82% /
tmpfs                 5.9G  276K  5.9G   1% /dev/shm
/dev/sda1             485M  116M  344M  26% /boot
/dev/mapper/vg_mei-lv_earthvar
                      3.0G  748M  2.1G  27% /var
/dev/mapper/vg_mei-lv_bacteriaroot
                      5.0G  3.9G  880M  82% /

I tried to unmount the device, but as shown below, it is busy.

[root@earth ~]# umount /dev/mapper/vg_mei-lv_bacteriaroot
umount: /: device is busy.
        (In some cases useful info about processes that use
         the device is found by lsof(8) or fuser(1))


I would have expected you could unmount it given that you're umounting by the device name.  Having it mounted on or over root likely makes this a bit finicky.
 
I tried to force unmount the device, but that failed also.

[root@earth ~]# umount -f /dev/mapper/vg_mei-lv_bacteriaroot
umount2: Device or resource busy
umount: /: device is busy.
        (In some cases useful info about processes that use
         the device is found by lsof(8) or fuser(1))
umount2: Device or resource busy


What other options are there.  Is there are way to get this unmounted
without having to shutdown my host system and boot into rescue mode.  I
don't really want to shutdown my active VM's while other staff are working
on them right now.

Take the advice of the output you pasted ... check the output from lsof and see if you can't narrow down the problem.

After you accidentally mounted that LV on root did you change your directory?  Something is hanging on to that device.
 

Please cc me directly as I only receive the daily digest.  Thanks.

Jeff
Meridian Environmental


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Mike
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