Mucking about with LVM and partitions isn’t really taxing, it’s all well documented. Trusting it however is a different matter. I’ve resized loads of Ext3 LVM partitions in the past, but was asked to resize a ReiserFS one today, which made me ask the question:

“Is there anything writing to it currently, as I will have to unmount it first ..”

Wrong assumption, or so says the guy sat next to me! ReiserFS can be dynamically resized on the fly! Woohoo says I, lets have a look at the resize_reiserfs man page!

We run a lot of Xen instances for our development and test servers and a few were starting to get full. Fortunately the disks in the real servers were very large and the xenlet partitions were made using LVM so resizing them to add more space was possible!

root@dev-myfiles0:~# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/hda1             4.0G  3.8G  200M  95% /
varrun                257M   48K  257M   1% /var/run
varlock               257M     0  257M   0% /var/lock
udev                  257M   40K  257M   1% /dev
devshm                257M     0  257M   0% /dev/shm

Basically we just have to shut down the xenlet, resize the partition and then restart the xenlet again, simple!