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/* Basic idea */
== Basic idea ==
The main idea to backup a VM or a VM-Template is, to divide the task into three subtasks:
* SnapshotcreateSnapshot: Save the machines state (CPUCreate a disk only snapshot. A new overlay file is created, Memory and Disk)all write operations are performed to this file. The underlying disk-image is now read only.* MergeexportSnapshot: Merge Copy the Diskread only disk-Image-Snapshot with image to the Live-Imagebackup location.* RetaincommitSnapshot: Export Commit the snapshot filesperformed write operations from the overlay back to the underlying (original) disk image. Now the underlying image is read-write again and the overlay image can be deleted.
A more detailed and technical description for these three sub-processes can be found [[#Sub-Processes | here]].
