I can confirm too, that this fixes the issue.
Here is the output of the command "apt-get update && apt-get install libdbd-mysql-perl" on my server:
OK:1 ftp://ftp.stratoserver.net/pub/linux/ubuntu xenial InRelease
OK:2 ftp://ftp.stratoserver.net/pub/linux/ubuntu xenial-updates InRelease...
Strange error during backups (manual or scheduled) on a server running Plesk Onyx, Version 17.0.17 Update #29 and Ubuntu 16.04 (all available updates were installed). Since today (21.07.2017) every backup action fails with an error message like this:
The backup log for such an action looks...