See also [[Libvirt_external_snapshot_with_GlusterFS]]
==== Snapshot ====
# Create a snapshot with state:#* If For the VM <code>vm-001</code> is running:commands see [[Libvirt_external_snapshot_with_GlusterFS#** Save the state of VM <code>vm-001</code> to the file <code>vm-001.state</code> (This file can either be created on a RAM-Disk or directly in the retain location. This example however saves the file to a RAM-Disk)Part_2: <syntaxhighlight lang="bash">virsh save vm-001 /path/to/ram-disk/vm-001.state</syntaxhighlight>#** After this command, the VMs CPU and memory state is represented by the file <code>/path/to/ram-disk/vm-001.state</code> and the VM <code>vm-001</code> is shut down.#* If the VM <code>vm-001</code> is shut down: #** Create a fake state file for the VM: <syntaxhighlight lang="bash">echo "Machine is not runnung, no state file" > /path/to/ram-disk/vm-001.state</syntaxhighlight># Move the disk image <code>/path/to/images/vm-001.qcow2</code> to the retain location: <syntaxhighlight lang="bash">mv /path/to/images/vm-001.qcow2 /path/to/retain/vm-001.qcow2</syntaxhighlight>#* '''Please note:''' The retain directory (<code>/path/to/retain/</code>) '''has to be''' on the same partition as the images directory (<code>/path/to/images/</code>). This will make the <code>mv</code> operation very fast (only renaming the inode). So the downtime (remember the VM <code>vm-001</code> is shut down) is as short as possible. #* '''Please note<sup>2</sup>:''' If the VM <code>vm-001</code> has more than just one disk-image, repeat this step for every disk-image# Create the new (empty) disk image with the old as backing store file: <syntaxhighlight lang="bash">qemu-img create -f qcow2 -b /path/to/retain/vm-001.qcow2 /path/to/images/vm-001.qcow2</syntaxhighlight>#* '''Please note:''' If the VM <code>vm-001</code> has more than just one disk-image, repeat this step for every disk-image# Set correct ownership and permission to the newly created image:#* <syntaxhighlight lang="bash">chmod 660 /path/to/images/vm-001.qcow2</syntaxhighlight>#* <syntaxhighlight lang="bash">chown root:vm-storage /path/to/images/vm-001.qcow2</syntaxhighlight>#* '''Please note:''' If the VM <code>vm-001</code> has more than just one disk-image, repeat these steps for every disk-image# Save the VMs XML description#* Save the current XML description of VM <code>vm-001</code> to a file at the retain location: <syntaxhighlight lang="bash">virsh dumpxml vm-001 > /path/to/retain/vm-001.xml</syntaxhighlight># Save the backend entry#* There is no generic command to save the backend entry (since the command depends on the backend). Important here is, that the backend entry of the VM <code>vm-001</code> is saved to the retain location: <code>/path/to/retain/vm-001.backend</code># Restore the VMs <code>vm-001</code> from its saved state (this will also start the VM): <syntaxhighlight lang="bash">virsh restore /path/to/ram-disk/vm-001.state</syntaxhighlight>#* '''Please note:''' After this operation the VM <code>vm-001</code> is running again (continues where we stopped it), and we have a consistent backup for the VM <code>vm-001</code>:#** The file <code>/path/to/ram-disk/vm-001.state</code> contains the CPU and memory state of VM <code>vm-001</code> at time T<sub>1</sub>#** The file <code>/path/to/retain/vm-001.qcow2</code> contains the disk state of VM <code>vm-001</code> at time T<sub>1</sub>#*** <font color="red">'''Important:'''</font> Remember: The live-disk-image <code>/path/to/images/vm-001.qcow2</code> still contains a reference to this file!! So you cannot delete or move it!!!#** The file <code>/path/to/retain/vm-001.xml</code> contains the XML description of VM <code>vm-001</code> at time T<sub>1</sub>#** The file <code>/path/to/retain/vm-001.backend</code> contains the backend entry of VM <code>vm-001</code> at time T<sub>1</sub># Move the state file from the RAM-Disk to the retain location (if you used the RAM-Disk to save the VMs state)#* <syntaxhighlight lang="bash">mv /path/to/ram-disk/vm-001.state /path/to/retain/vm-001.state</syntaxhighlight>_Create_the_snapshot_using_virsh]]
See also: For the workflow see [[stoney_conductor:_prov_backup_kvm_prov-backup-kvm#Snapshot | Snapshot workflow createSnapshot]]
==== Merge ====
