Fedora Cookbook: Resizing a logical volume

[Luciano Rocha]

On Fri, Dec 28, 2007 at 12:02:40PM +0100, moi wrote:
>  Root FS resizes imho usually requires the Rescue mode. Perhaps when growing, 
>  but shrinking is a bit tough...

Growing can be done on-line. That means no interruption of service, no
need to umount the filesystem, etc..

Shrinking must be off-line, still. And in XFS, shrinking isn't supported
at all.

> 
>  You may - in rescue mode - import the Volume Group (when using LVM) and do 
>  the resize operations.

Note that usually there's no symlinks for lvm utilities in the rescue
mode of the installer, so you'll have to use the following syntax:
lvm vgscan
lvm lvresize
...

> Do not forget to do a partprobe /dev/xda, as the 
>  kernel will still be using the old filesystem tables when resizing

Eh? No, that's not needed, The lvm partitions aren't /dev/hdx or sdx.
You do have to rescan the partition table if you changed the partition
of the PV device.

> (one of 
>  our customers did a shrink on the root partition and ran fsck, this made a 
>  lot of errors afterwards).

Oh, that's bad. Very bad. You don't shrinking filesystem after shrinking
the block device, you do it *before*. That's the opposite of growing.

I.e.:
* lvm vgscan
* lvm vgchange -ay
* resize2fs /dev/foo/bar 10G
* lvm lvresize -L 10G foo/bar

-- 
lfr
0/0
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