Export a VM

[olivierlambert]

We need to export a VM in a specific path (like in xo-cli).

Needed arguments:

• [ ] --export (the main one)
• [ ] --compress (by default, compressed)
• [ ]  --timestamp (add a timestamp in the name of all exported VMs. NOT enabled by default. See rotation paragraph for more)

The last arg should be the destination path. By default, the current folder. Because xo-backup will work in batch (or with a selector), there is no sense to give a filename argument (I think?)

About the rotation: because it seems complicated to rotate exported files, maybe the best strategy is to export VMs automatically with their name (without timestamp) and rewrite the old file. Indeed, exporting files is really useful for Disaster Recovery. For rolling backups, snapshots or file-based rsync are more appropriated.

[julien-f]

Note: To avoid corrupted exports, they should be written on the disk atomically.