Libvirt Plugin: Limitations

Bacula Enterprise Only

This solution is only available for Bacula Enterprise. For subscription inquiries, please reach out to sales@baculasystems.com.

The following article presents limitations of the Bacula Enterprise Libvirt Plugin.

Backup Strategy

The Bacula Enterprise Libvirt Plugin uses QCOW2-format checkpoints on disks,with all the implications associated with this approach. Since snapshots are not used as the backup strategy, the state of the virtual machine is not saved. However, this method provides more efficient disk backups.

When using the external_snapshot backup method, the plugin does not save the state of the virtual machine.

This limitation is expected to be removed in future versions.

Backup Disks Format

The Bacula Enterprise Libvirt Plugin supports the checkpoint backup method only with the QCOW2 disk format. For compatibility with RAW disks, the external_snapshot or block_dev backup methods can be used. Each of these methods has the following limitations:

The external_snapshot method performs full backups only.

The block_dev method retains checkpoints only until the domain is off.

Specific Manual Backup Port in Parallel Jobs

The Bacula Enterprise Libvirt Plugin uses the NBD protocol to retrieve disk data. For this reason, the plugin exposes all virtual machine disks through NBD on the same port.

If parallel backup jobs are required for different virtual machines, a dedicated port must be manually assigned using the nbd_server_port and nbd_client_port parameters for each Bacula Fileset.

This limitation is expected to be removed in future versions.