[CentOS-virt] Need to unmount an LV from host system

Wed Mar 6 06:55:46 UTC 2013
Gabriele Matteelli <gabriele at matteelli.it>

Il 05/03/2013 21:24, jboyce at meridianenv.com ha scritto:
> 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 /.
>
> [root at 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 at 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 tried to force unmount the device, but that failed also.
>
> [root at 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.
>
> Please cc me directly as I only receive the daily digest.  Thanks.
>
> Jeff
> Meridian Environmental
>
>
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I don't know if this is usefull to you but you can try one of these:
mount --bind olddir newdir
or
mount -o remount olddir newdir
or
mount --move olddir newdir

Hope this can help you.

Sincerely,
Gabriele Matteelli