Monthly Archive for May, 2012

Easily Resize LVs and Underlying Filesystems

Part of the reason I use Logical Volumes for my block devices rather than standard partitions is because LVs are much more flexible when it comes to sizing/resizing.

For example, in a particular setup you might have a 1 TB hard drive that you want to be broken up into two block devices. You could either choose two 500 GB partitions, or two 500 GB LVs. If you use partitions and later find out that you really needed 300 GB for one and 700 GB for the other then resizing might get a little complicated. On the other hand, with LVs resizing is simple!

LVM has the ability to resize the LV and the underlying filesystem at the same time (it uses fsadm under the covers to resize the filesystem which on my system supports resizing ext2/ext3/ext4/ReiserFS/XFS). In order to pull this off simply use lvresize along with the --resizefs option. An example of this command is shown below:

dustymabe@fedorabook: tmp>sudo lvresize --size +1g --resizefs /dev/vg1/lv1 [sudo] password for dustymabe: fsck from util-linux 2.19.1 /dev/mapper/vg1-lv1: clean, 11/262144 files, 51278/1048576 blocks Extending logical volume lv1 to 5.00 GiB Logical volume lv1 successfully resized resize2fs 1.41.14 (22-Dec-2010) Resizing the filesystem on /dev/mapper/vg1-lv1 to 1310720 (4k) blocks. The filesystem on /dev/mapper/vg1-lv1 is now 1310720 blocks long. dustymabe@fedorabook: tmp>

It should be noted that you can only do online resizing when you are making an LV larger. If you are making it smaller then the filesystem will most likely need to be unmounted.

Happy Resizing!
Dusty Mabe