More work on virtnbdbackup

Had some time to add more features to my libvirt backup utility, now it supports:

  • Added backup mode differencial.
  • Save virtual domains UEFI bios, initrd and kernel images if defined.
  • virtnbdmap now uses the nbdkit COW plugin to map the backups as regular NBD device. This allows users to replay complete backup chains (full+inc/diff) to recover single files. As the resulting device is writable, one can directly boot the virtual machine from the backup images.

Check out my last article on that topic or watch it in action.

Also, the dirty bitmap (incremental backup) feature now seems to be enabled by default as of newer qemu and libvirt (8.2.x) versions.

As a side note: still there’s an RFP open, if one is interested in maintaining, as i find myself not having a valid key in the keyring.. laziness.

Written on June 29, 2022