Virsh vol-clone

External

• https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Virtualization_Deployment_and_Administration_Guide/sect-Storage_Volumes-Cloning_volumes.html
• https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Virtualization_Deployment_and_Administration_Guide/sect-Managing_guest_virtual_machines_with_virsh-Storage_Volume_Commands.html#sect-Creating_storage_volumes-Cloning_a_storage_volume

Internal

• virsh

Overview

The operation clones the source volume within the same storage pool, It allocates space for the target volume and copies the content across. Various optimizations are applied depending on the source volume format.

virsh vol-clone --pool <storage-pool-name> <source-volume-name> <new-volume-name>

The virsh man page does not explicitly require it, but it is probably better to make sure the source volume is not in use while cloning.

For qcow2 volumes for qcow2 images which don't support full allocation, --prealloc-metadata can be used. --prealloc-metadata preallocates metadata and creates a sparse image file with metadata, resulting in higher performance compared to images with no preallocation and only slightly higher initial disk space usage.

Examples

Cloning a Raw Volume

Do I need to shut down the guest using the source volume, or umount the source volume before cloning? For the time being, until I document the requirements, I will umount

virsh vol-clone --pool main-storage-pool test-volume test-volume.raw
virsh vol-list --pool main-storage-pool

Cloning a qcow2 Volume

virsh vol-clone --pool storage-pool-name --prealloc-metadata source-volume target-volume

Example:

virsh vol-clone --pool main-storage-pool --prealloc-metadata template.qcow2 node1.qcow2
Vol node1.qcow2 cloned from template.qcow2

virsh vol-list --pool main-storage-pool

Other Virtualized Storage Operations