Sync both server snapshots with what the live machines run, and keep their backup tooling

server/home/systemd/media-backup.service

@@ -0,0 +1,19 @@
+[Unit]
+Description=Weekly copy of the Media pool to the Backup pool
+Documentation=file:///home/gib/Server/RESTORE.md
+After=zfs-mount.service
+Wants=zfs-mount.service
+RequiresMountsFor=/home/gib/Public /home/gib/.local/share/Backup
+
+[Service]
+Type=oneshot
+ExecStart=/usr/local/sbin/media-backup
+# 8.6 TB on the first run, deltas after. Generous, but bounded so a hung rsync
+# fails loudly instead of overlapping next week's fire.
+TimeoutStartSec=24h
+Nice=10
+IOSchedulingClass=best-effort
+IOSchedulingPriority=7
+
+[Install]
+WantedBy=multi-user.target