Resize a VM disk

ZRS can increase the capacity of a qcow2 or raw disk image while the VM is running or stopped. Disk shrinking is not supported.

Increase disk capacity #

1. Open the VM and find the disk in Disks.
2. Open the disk’s actions and select Resize.
3. Enter the total capacity under New size and select GiB or TiB. For example, to grow a 40 GiB disk by 20 GiB, enter 60 GiB.
4. Check Current size, the reported growth, and Space left in pool.
5. Select Resize and review any additional confirmation.

The disk’s capacity updates after the operation completes.

Expand storage inside the guest #

ZRS increases the disk image’s capacity. The guest operating system may expand its partitions and filesystems automatically, depending on its configuration. Otherwise, expand them with the guest’s storage tools.

Resizing with snapshots #

Reverting to an earlier snapshot can restore the disk’s previous size, discarding changes made after that snapshot.

When Resize is unavailable #

The disk must be a qcow2 or raw image in a supported, active storage pool. A VM with saved memory must be started before resizing.

Resizing is also blocked when:

• The image file is missing.
• Another disk uses the image as a backing file.
• The image uses qcow2 version 2 and contains internal snapshots.