[linux-lvm] Mounting two logical volumes to the same mount point

[Aad Rijnberg]

On Wednesday 21 June 2006 10:24, Heinz Mauelshagen wrote:
> On Tue, Jun 20, 2006 at 09:07:29PM +0200, Aad Rijnberg wrote:
> > Hi,
> >
> > my logical volume that contains /usr appears to be too small. I already
> > removed some applications that I did not need, but it is still on the
> > edge. Now that there are a lot of updates, I get the complaint of yum
> > that there is not enough free space on /usr.
> >
> > I just bought an additional harddisk which I also needed for other
> > purposes, and would like to reserve part of this new drive for extra LVM
> > space. I have just created a new volume group (VolGroup01) on the new
> > drive, and a logical volume (LogVol01) inside that physical volume group.
> >
> > Can I mount both /dev/mapper/VolGroup00-LogVol01 (which contains the /usr
> > data on the "old" drive) and /dev/mapper/VolGroup01-LogVol01 to the /usr
> > mount point? Or can only one logical volume be mounted to a mount point?
>
> Aad,
>
> you can only mount one device with a filesystem on the same mountpoint.
>
> What needs doing in order to grow your logical volume containing the usr
> filesystem, is to *add* the second drive to the existing volume group on
> the first one and grow usr afterwards (LV and FS).
>
> Carry out the follwoing steps (or use system-config-lvm):
>
> lvremove VolGroup01/LogVol01
> vgremove VolGroup01
> vgextend VolGroup00 /dev/sdb # or whatever the drive is
>
> # replace 5G with the capacity you want to add
> lvextend -L+5G VolGroup00/LogVol01
>
> How to grow the FS depends on the type; for ext2/3 you'ld run:
>
> ext2online /dev/VolGroup00/LogVol00
>
Hi Heinz and Georg,

thanks for the clear descriptions.

I performed the operations with the Logical Volume Management tool provided 
with Fedora Core 5 (system-config-lvm), which has an intuitive GUI and now 
my /usr "partition" has grown by 5G. It's as easy as ... ;-)

Thanks for the support!

Aad