Rebuilding a virtual machine from a snapshot

If you want to create a new virtual machine based on a snapshot of an existing virtual machine at a specific point in time without affecting the existing virtual machine, you can rebuild a new virtual machine from the snapshot.

Prerequisite

The virtual machine already has snapshots. You can check if snapshots exist for this virtual machine on the Snapshot tab in the virtual machine details panel.

Precaution

• If the source virtual machine has CPU exclusive enabled, the virtual machine rebuilt from the snapshot will have CPU exclusive disabled by default. You may manually enable it during or after the rebuild.
• A virtual machine rebuilt from a snapshot does not retain shared volumes, GPU passthrough devices, vGPUs, SR-IOV passthrough NICs, PCI passthrough NICs, or USB devices.
• Modifying the capacity and bus type of disks already in the snapshot is not supported during rebuild.
• Changing the cluster information in the snapshot is not supported during rebuild.
• When you rebuild a virtual machine from a snapshot, the storage policy of the virtual volume will follow the one in the snapshot. You can also modify it. If the number of hosts in the cluster to which the virtual machine belongs does not meet the configuration requirements of the virtual volume storage policy in the snapshot, the default storage policy of the cluster will be used.
• When a snapshot contains a VPC NIC, the VPC and subnet of VPC NIC of the virtual machine remain consistent with those in the snapshot. You can also modify it. If the VPC NIC also uses a floating IP, the floating IP field will be left blank and must be selected manually.

Procedure

1. In the VM snapshot list or the Snapshot tab of the virtual machine details panel, locate the snapshot for the virtual machine to be rebuilt.

   If there are many snapshots, you can quickly locate the target snapshot by searching for its name.

2. Click the ellipsis (...) to the right of the snapshot and select Rebuild.

3. In the pop-up Rebuild VM dialog box, fill in the basic configuration information of the virtual machine. For details, refer to Basic configuration information. Once done, click Next.

   Note:

   If you have modified any of the following attributes of the virtual volumes on the rebuilt virtual machine, only Full-copy rebuilding is supported when setting the Creation method.

   • Redundancy policy
   • Provisioning (from Thick provisioning to Thin provisioning)
   • Data encryption

4. Fill in other configurations for the virtual machine. For details, refer to the section on Other configurations. You also need to configure the Creation method for the virtual machine.

   • Fast-copy rebuilding: Completes in seconds. The new virtual machine will occupy less space as it will share the data blocks with the source volumes. When data changes occur in the new virtual machine, performance may degrade until the corresponding data blocks are fully owned by the VM.
   • Full-copy rebuilding: The completion time is proportional to the data size. A full copy creates a new virtual machine by copying data from the source volume. Although it consumes more storage space, its performance is independent of the source volume.

5. After filling in all the configuration information, click Rebuild VM.

   During the process, you can check the task progress and whether the task is successful in the Task center.

   If the ISO image mounted in the virtual machine is not stored in the associated cluster of the virtual machine, you can click the ellipsis (...) in the upper-right corner of the task during ISO image distribution and select Stop to terminate the virtual machine rebuild task.

   If the rebuilt task includes multiple ISO images, stopping the operation will cancel the distribution of the current and any remaining ISO images that have not been completed. Any distributed images will be retained.