Changes
= Overview =
This page describes how the VMs and VM-Templates are backed-up inside the [http://www.stoney-cloud.org stoney cloud].
= Basic idea =
The main idea to backup a VM or a VM-Template is, to divide the task into three subtasks:
* Snapshot: Save the machines state (CPU, Memory and Disk)
* Merge: Merge the Disk-Snapshot with the live-image
* Retain: Export the snapshot files
A more detailed and technical description for these three sub-processes can be found in the following sub-chapters.
== Snapshot ==
# Create a snapshot with state:
#* Save the VMs state: <code>virsh save my-vm my-vm.state</code>
#* Rename the actual disk image: <code>mv my-vm.qcow2 my-vm-backup.qcow2</code>.
#* Create the new disk image with the old as backing file: <code>qemu-img create -f qcow2 -b my-vm-backup.qcow2 my-vm.qcow2</code>.
#* Set correct ownership and permission to the newly created image:
#** <code>chown root:vm-storage my-vm.qcow2</code>.
#** <code>chmod 660 my-vm.qcow2</code>.
#* Restore the VMs state: <code>virsh restore my-vm.state</code>.
# Merge the disk images my-vm.qcow2 and my-vm-snap.qcow2 to a single image: <code>virsh qemu-monitor-command my-vm --hmp "block_stream drive-virtio-disk0"</code>.
# Move the files to the backup location:
#* Move the old disk image to the backup location and add the date as suffix to not overwrite older backups: <code>mv my-vm-backup.qcow2 /path/to/backup/my-vm-backup.qcow2.date</code>
#* Move the state file to the backup location and add the date as suffix to not overwrite older backups: <code>mv my-vm.state /path/to/backup/my-vm.state.date</code>
== Merge ==
== Retain ==
= State of the art =
= Next steps =
[[Category: stoney conductor]]
