[Unit]
Description=Second copy of /mnt/backup to router USB disk (rclone SFTP)
Wants=network-online.target
After=network-online.target
RequiresMountsFor=/mnt/backup

[Service]
Type=oneshot
ExecStart=/usr/bin/flock -n /run/lock/router-backup.lock /usr/local/bin/router-backup run
ExecStopPost=/usr/local/bin/backup-metrics backup_router
Nice=10
IOSchedulingClass=idle
# первичная копия ~370 ГБ при ~8 МБ/с — около 13 ч
TimeoutStartSec=infinity