I was able to get UrBackup (from the Xenial PPA) and ZFS working on Ubuntu Focal 20.04 with a little difficulty.
The problem: UrBackup doesn’t detect ZFS volumes.
Example:
urbackup_snapshot_helper test
…
Testing for zfs…
TEST FAILED: Creating test zfs volume “xxx/images/testA54hj5luZtlorr494” failed
The reason for the problem:
find_zfs_cmd() in the urbackup_snapshot_helper binary calls zfs --version and expects a return code of 2 (the --version switch is not supported in Xenial ZFS 0.6.5). zfs --version IS supported in Focal 0.8.3 and has a return code of 0. find_zfs_cmd() fails on return code of 0.
Hacked-together solution until this is addressed in UrBackup:
Step 1: mv /sbin/zfs /sbin/zfs-original
Step 2: Create a new bash script named /sbin/zfs with identical ownership/permissions and the following contents
#!/bin/bash
zfs-original "$@"
original_return_code="$?"
if [[ "$@" == "--version" ]]
then
exit 2
fi
exit $original_return_code
