Difference between revisions of "stoney conductor: VM Backup"
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== Retain == | == Retain == | ||
− | + | # 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> | ||
= State of the art = | = State of the art = |
Revision as of 13:49, 22 October 2013
Overview
This page describes how the VMs and VM-Templates are backed-up inside the 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 state of VM
vm-001
to the filevm-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 VMvm-001
is shut down.
- Save the state of VM
- Move the disk image
/path/to/images/vm-001.qcow2
to the retain location:mv /path/to/images/vm-001.qcow2 /path/to/retain/vm-001.qcow2
- Please note: The retain directory (
/path/to/retain/
) has to be on the same partition as the images directory (/path/to/images/
). This will make themv
operation very fast (only renaming the inode). So the downtime (remember the VMvm-001
is shut down) is as short as possible.
- Please note: The retain directory (
- Create the new (empty) disk image with the old as backing store 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
.
- Set correct ownership and permission to the newly created image:
Merge
- 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"
.
Retain
- 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
- Move the old disk image to the backup location and add the date as suffix to not overwrite older backups: