Backup

Bacula Enterprise Only

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

If you choose not to utilize the cluster_mode option in your filesets for a Failover Cluster configuration, your backups will be limited to the VMs on the node where the File Daemon is installed, as long as they match your include/exclude settings. However, you have the option to install a file daemon on each node. On the other hand, if you do specify cluster_mode, the Hyper-V WinAPI Plugin will identify all VMs that meet your include/exclude settings across the entire cluster, including remote nodes that are accessible. It will then attempt to migrate remote VMs locally before performing the backup. Once the backup is complete, the VM will be automatically migrated back to its original node.

The files backed up from the Hyper-V server will be visible in a bconsole or will have the prefix /@HYPERV-WINAPI/.

Typically, a VM backup data is organized as follows:

/@HYPERV-WINAPI/0bc0f01d-b3e5-4b13-b0e3-bf5490c828b9-test1
/@HYPERV-WINAPI/0bc0f01d-b3e5-4b13-b0e3-bf5490c828b9/IDE00.out
/@HYPERV-WINAPI/0bc0f01d-b3e5-4b13-b0e3-bf5490c828b9/IDE00.bhd
/@HYPERV-WINAPI/0bc0f01d-b3e5-4b13-b0e3-bf5490c828b9/IDE00.bmp
/@HYPERV-WINAPI/0bc0f01d-b3e5-4b13-b0e3-bf5490c828b9/IDE01.out
/@HYPERV-WINAPI/0bc0f01d-b3e5-4b13-b0e3-bf5490c828b9/IDE01.bhd
/@HYPERV-WINAPI/0bc0f01d-b3e5-4b13-b0e3-bf5490c828b9/IDE01.bmp
/@HYPERV-WINAPI/0bc0f01d-b3e5-4b13-b0e3-bf5490c828b9/test1.bvm

Where:

0bc0f01d-b3e5-4b13-b0e3-bf5490c828b9 is the VM UID of the “test1”
0bc0f01d-b3e5-4b13-b0e3-bf5490c828b9-test1 is a convenience empty file reminding us that the content of the VM named test1 is saved into folder /0bc0f01d-b3e5-4b13-b0e3-bf5490c828b9/
each drive is named after its controller type (IDE, SCSI), its controller number and its location in the controller. IDE00 meaning: IDE controller number 0, location 0.
each .bhd file contains attributes information on the drive
each .out file is the actual content of the drive
each .bmp file gives information on how the content of the .out file maps onto the original drive and is needed for Single Item Restore
the .bvm file backups information on the virtual machine itself

Incremental-Differential backups: the Hyper-V WinAPI Plugin will automatically follow the backup level strategy as scheduled in Bacula.

Consistency Level: A backup can fail when the option “Application Consistent” is required for a VM that doesn’t support it.

If an Application Consistent backup fails, the Hyper-V WinAPI Plugin will change automatically the Consistency Level to “Crash Consistent” and retry.
Only if allow_pre_save is enabled, when a “Crash Consistent” backup fails, the Hyper-V WinAPI Plugin will change the pre_backup_action to “Save” and post_backup_action to “Restart” and retry.
Migration from a distant node, current backup checkpoint and pre_backup_action are stored into the corresponding VM notes in a proprietary format. They are removed when the backup is successful. If some interruption occurs during the backup, they can be recovered afterwards.
If none of the above works, the backup fails with Error.
Some reference points are maintained on Hyper-V side by Bacula, corresponding to different snapshots backed up. Bacula will prune those reference points when needed to keep at most 4.