Question

You maintain a reporting server. A daily cleanup script should run at 02:00, but only when the machine happens to be powered on at that time (no catch-up runs are wanted if the server was off). You have created cleanup.service and want to trigger it via a systemd timer. Which OnCalendar timer configuration meets these requirements without any missed-run recovery?

Accepted Answer

Set [Timer] OnCalendar=*-*-* 02:00:00 and leave Persistent unset (defaults to false)

Answer

Set [Timer] OnCalendar=daily with Persistent=true

Answer

Set [Timer] OnBootSec=2h with Persistent=true

Answer

Set [Timer] OnCalendar=*-*-* 02:00:00 with Persistent=true