Backup and Restore Strategies

Image Backup

With the image backup level strategy, the Bacula Enterprise Proxmox Plugin will save the Client disks as raw images for QEMU VMs and as a tar archives for LXC VMs, in the Proxmox context.

For this to work, it is not needed a Bacula File Daemon in each guest VM. The Bacula Proxmox Plugin will contact the Proxmox hypervisor to read and save the contents of virtual machine disks using snapshots (default behavior) and dump them using the Proxmox API.

Bacula does not need to walk through the Client filesystems to open, read, close and stat files, so it consumes less resources on the Proxmox infrastructure than a file level backup on each guest machine would. On the other hand, Bacula will also read and save useless data such as swap files or temporary files.

The Proxmox Plugin will save not only the disk images of the guest VM, but also guest VM configurations which allows for very easy guest VM restores.

Installing Bacula Client on Each Guest

With this first strategy, you do not use the Bacula Enterprise Proxmox Plugin, but instead install a Bacula Enterprise File Daemon inside every virtual machine as if they were normal physical clients. In order to optimize the I/O usage on your Proxmox system, you will use Bacula’s Schedules, Priorities, and Job concurrency settings to spread backup jobs throughout the backup window. Since all guest VMs could use the same storage on the Proxmox hypervisor, running all your backup jobs at the same time can create a bottleneck on the disk/network subsystem.

Installing a Bacula Enterprise File Daemon in each virtual machine permits you to manage your virtual servers like physical servers and also to use all Bacula Enterprise’s features such as:

Quick restores of individual files.
Checksum of individual files for Virus and Spyware detection.
Verify Jobs.
File or Directory exclusion (such as swap or temporary files).
File level compression.
Accurate backups.