Unison, systemd and logrotate

I have unison running under systemd to keep my local and remote NASs in sync. The systemd config is thus: [Unit] Description=NAS Unision service After=network.target StartLimitIntervalSec=0 [Service] Type=simple Restart=always RestartSec=1 User=nas ExecStart=/usr/bin/unison borg [Install] WantedBy=multi-user.target And in ~nas/.unison/borg.prf I have configure unison to run with: # Keep repeating every 15 mins. repeat=900 # Log to the file which will be rotated by logrotate. log=true logfile=/var/log/unison-borg.log logrotate is configure to rotate the log once per day: # Rotation of the Unision logs /var/log/unison-borg.log { dayly rotate 7 compress delaycompress missingok notifempty create 644 nas nas } My issue is that unison doesn't appear to open the log file with each repeat and thus when logrotate rotates the log file unsion-borg.log.1 gets the updates. The man file for unison states that "Sending SIGUSR1 will close the logfile; the logfile will be re-opened (and created, if needed) automatically, to allow for log rotation." How should I do this in systemd?