Revision as of 13:41, 22 October 2013

Overview

This page describes how the VMs and VM-Templates are backed-up inside the stoney cloud.

The main idea to backup a VM or a VM-Template is, to divide the task into three subtasks:

A more detailed and technical description for these three sub-processes can be found in the following sub-chapters.

Create a snapshot with state:
- Save the state of VM vm-001 to the file vm-001.state:
```
virsh save vm-001 vm-001.stat
```
- After this command, the VMs CPU and memory state is represented by the file vm-001.state and the VM vm-001 is shut down.
- Move the disk image /path/to/vm-001.qcow2 to the retain location:
```
mv /path/to/vm-001.qcow2 /path/to/retain/vm-001.qcow2
```
  .
- Create the new disk image with the old as backing file: qemu-img create -f qcow2 -b my-vm-backup.qcow2 my-vm.qcow2.
- Set correct ownership and permission to the newly created image:
  - chown root:vm-storage my-vm.qcow2.
  - chmod 660 my-vm.qcow2.
- Restore the VMs state: virsh restore my-vm.state.
Merge the disk images my-vm.qcow2 and my-vm-snap.qcow2 to a single image: virsh qemu-monitor-command my-vm --hmp "block_stream drive-virtio-disk0".
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: mv my-vm-backup.qcow2 /path/to/backup/my-vm-backup.qcow2.date
- Move the state file to the backup location and add the date as suffix to not overwrite older backups: mv my-vm.state /path/to/backup/my-vm.state.date

@@ Line 11: / Line 11: @@
 == Snapshot ==
 # Create a snapshot with state:
-#* Save the state of VM <code>my-vm</code> to the file <code>my-vm.state</code>: <syntaxhighlight lang="bash">virsh save my-vm my-vm.stat</syntaxhighlight>
+#* Save the state of VM <code>vm-001</code> to the file <code>vm-001.state</code>: <syntaxhighlight lang="bash">virsh save vm-001 vm-001.stat</syntaxhighlight>
-#* Rename the actual disk image: <code>mv my-vm.qcow2 my-vm-backup.qcow2</code>.
+#* After this command, the VMs CPU and memory state is represented by the file <code>vm-001.state</code> and the VM <code>vm-001</code> is shut down.
+#* Move the disk image <code>/path/to/vm-001.qcow2</code> to the retain location: <syntaxhighlight lang="bash">mv /path/to/vm-001.qcow2 /path/to/retain/vm-001.qcow2</syntaxhighlight>.
 #* 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: