Expand a Qemu Disk

I exhausted the disk space on my Windows VM and found I needed more room. This is one of those lovely tasks that actually has simple and good documentation and works easily enough.

I followed these instructions using qemu-resize:

https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/virtualization_deployment_and_administration_guide/sect-using_qemu_img-re_sizing_the_disk_image

But you might find this just as helpful:

https://maunium.net/blog/resizing-qcow2-images/

Here is another read on using virt-resize instead of qemu-resize but a little more to it:

https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/virtualization_administration_guide/sect-expand-disk-image

After the disk was enlarged, I wondered how I might verify it. virt-df only shows the existing filesystem, and since it only changed the partition, nothing in that output changed. I suppose the command virt-list-partitions might show a difference, but I didn’t have that on my system and didn’t want to go looking for it.

Booting into my Windows VM and verifying I had 20G newly available was simple enough. I used the Computer Management > Storage > Disk Management interface and followed the GUI wizard steps for expanding a volume by Right Clicking on the drive and selecting Extend Volume.