You can save the current state of a VM file system or user data by creating a snapshot of a volume. A snapshot of a boot volume may be useful, for example, before updating VM software. If anything goes wrong, you will be able to revert the VM to a working state at any time. A snapshot of a data volume can be used for backing up user data and testing purposes.
- To create a consistent snapshot of a running VM’s volume, the guest tools must be installed in the VM, as described in Installing guest tools. The QEMU guest agent included in the guest tools image automatically quiesces the filesystem during snapshotting.
To create a snapshot of a volume
To manage a volume snapshot
Select a volume and open the Snapshots tab on its right pane.
You can do the following:
- Create a new volume from the snapshot.
- Create a template from the snapshot.
Discard all changes that have been made to the volume since the snapshot was taken. This action is available only for VMs with the "Shut down" and "Shelved offloaded" statuses.
As each volume has only one snapshot branch, all snapshots created after the snapshot you are reverting to will be deleted. If you want to save a subsequent snapshot before reverting, create a volume or an image from it first.
- Change the snapshot name and description.
- Reset the snapshot stuck in an "Error" state or transitional state to the "Available" state.
- Remove the snapshot.
To perform these actions, click the ellipsis button next to a snapshot, and then click the corresponding action.