[Unit]
Description=Run backup service daily at 22:22 with random delay
Requires=backup.service

[Timer]
# Run daily at 22:22
OnCalendar=*-*-* 22:22:00
# Add random delay up to 5 minutes (300 seconds)
RandomizedDelaySec=300
# Catch up on missed runs if system was down
Persistent=true
# Don't run if system is on battery (if applicable)
WakeSystem=false

[Install]
WantedBy=timers.target