"Wie Sie Youtube-Videos ohne Unterbrechung schauen" Hä? Wieso Unterbrechung? Ich hab bei #Youtube keine Unterbrechungen! "Wer Youtube ohne Werbung schauen möchte, muss ein Premium-Abo kaufen" FALSCH! "Wir stellen Alternativen vor, die nichts kosten" Aha. In einem Plus-Artikel, für den ich bezahlen muss? Ihr seid ja Vögel! #adblock #ublockorigin #masterrace

that does not work if the backup takes too long. So not a proper solution IMHO.

Also, the "After=" directive seems to be not really a solution, as mail-sync should work even if backup hasn't run yet, and the other way around... 🤔

FWIW using the "Conflicts=" directive as suggested here: https://unix.stackexchange.com/a/224091 is not really an option, as a mail-sync should not cancel the backup and vice-versa, right? 😆

so there is https://lists.freedesktop.org/archives/systemd-devel/2019-October/043586.html and https://superuser.com/questions/1492025/systemd-how-to-make-two-services-mutually-exclusive-but-run-both on that subject, but without a systemd-native approach, just `flock` as a workaround. I really am cursious, isn't that something that's rather common (having two services that shall not run at the same time)?