Dirk große Osterhues

After running virtual machines in KVM for some time, it might come in handy to be able to resize a KVM guest's raw volumes. In order to do so you first have to shutdown your VM:

virsh destroy <guestname>

In order to add an additional 2 gig to your respective machine, you do the following:

qemu-img resize <diskname>.img +2G

Now restart the machine:

virsh start <guestname>

Then use fdisk inside the guest to make use of the new space:

fdisk /dev/vda

There, you delete the respective partition and immediately recreate it - with more space. Now restart the machine in order to let the kernel make note of the changes:

reboot

After a final resize you're able to make use of the sweet new space:

resize2fs /dev/vda1

Voila!