[CentOS] LVM

[Ray Van Dolson]

On Sun, Mar 18, 2012 at 08:04:14PM +0100, Markus Falb wrote:
> On 18.3.2012 18:34, madunix at gmail.com wrote:
> > I need to shrink /home(755G) to 150GB and use free space to add to the
> > existing /(50G).
> > #df -kh
> > Filesystem           Size  Used Avail Use% Mounted on
> > /dev/mapper/vg_web-lv_root 50G  7.8G   40G  17% /
> > tmpfs                 7.8G  384K  7.8G   1% /dev/shm
> > /dev/sda2             485M   79M  381M  18% /boot
> > /dev/sda1             200M  256K  200M   1% /boot/efi
> > /dev/mapper/vg_web-lv_home755G  6.2G  711G   1% /home
> > 
> > Need to have the step, can this be done online or need to go offline
> > (umount) the file systems.
> 
> What filesystem? Assuming ext3, this cannot shrunk without unmounting.
> I believe the following *should* work for ext3
> 
> $ umount /home
> $ e2fsck -f /dev/vg_web/lv_home
> $ resize2fs /dev/vg_web/lv_home 150g
> $ lvresize -L 150g /dev/vg_web/lv_home
> $ mount /home
> 
> I am not sure how safe it is. Take care!

I was under the impression that you needed to unmount the file system
to shrink it with resize2fs (you can grow it online however).

Ray