We will create a systemd.timer to rotate Postfix’s log files created by the postlogd. Timers can be triggered by systemd dependencies or based on different events. Jobs triggered by timers can be configured to run in specific environments and their configuration files end on “.timer”.

Each timer file requires a matching unit file.

Our timer will trigger a simple postfix-logroate.service every Sunday at 00:00h.

/usr/lib/systemd/system/postfix-logrotate.timer

[Unit]
Description=Rotate Postfix logfiles on a weekly basis

[Timer]
Unit=postfix-logrotate.service
OnCalendar=Sun *-*-* 00:00:00

[Install]
WantedBy=timers.target

/usr/lib/systemd/system/postfix-logrotate.service

[Unit]
Description=Rotates logs maintained by Postfix postlogd
Wants=postfix-logrotate.timer

[Service]
Type=oneshot
ExecStart=/usr/sbin/postfix logrotate

[Install]
WantedBy=multi-user.target

We can interact with timers in the same way that we interact with services using the systemctl command.

systemctl status postfix-logrotate.timer
● postfix-logrotate.timer - Rotate Postfix logfiles on a weekly basis
     Loaded: loaded (/usr/lib/systemd/system/postfix-logrotate.timer; enabled; preset: enabled)
     Active: active (waiting) since Fri 2026-05-29 13:36:43 CEST; 3 days ago
 Invocation: 0ccf705c63d847a8a36503d383666db7
    Trigger: Sun 2026-06-07 00:00:00 CEST; 5 days left
   Triggers: ● postfix-logrotate.service

May 29 13:36:43 edi systemd[1]: Started postfix-logrotate.timer - Rotate Postfix logfiles on a weekly basis.

systemctl list-timers postfix-logrotate
NEXT                           LEFT LAST                                PASSED UNIT                    ACTIVATES                
Sun 2026-06-07 00:00:00 CEST 5 days Sun 2026-05-31 00:00:05 CEST 1 day 21h ago postfix-logrotate.timer postfix-logrotate.service