Make Nextcloud NAS backups independent, verified and retryable

systemd/user/nextcloud-borg-backup.service

@@ -1,13 +1,20 @@
 [Unit]
-Description=Back up mounted Nextcloud folder to Synology with Borg
+Description=Verified Nextcloud backup to NAS (independent of desktop mount)
 Documentation=man:borg(1)
+StartLimitIntervalSec=0
 
 [Service]
 Type=oneshot
-ExecStart=%h/.local/bin/nextcloud-borg-backup backup
+ExecStart=%h/.local/bin/nextcloud-borg-backup backup --if-due
 TimeoutStartSec=12h
+TimeoutStopSec=30s
+KillMode=control-group
 Nice=10
 IOSchedulingClass=best-effort
 IOSchedulingPriority=6
+UMask=0077
+NoNewPrivileges=true
 Environment=LANG=C.UTF-8
 Environment=LC_ALL=C.UTF-8
+Environment=BORG_LOCK_WAIT=60
+Environment=BORG_NON_INTERACTIVE=1

systemd/user/nextcloud-borg-backup.timer

@@ -1,10 +1,12 @@
 [Unit]
-Description=Daily Nextcloud Borg backup timer
+Description=Check every 15 minutes for due or failed Nextcloud NAS backup
 
 [Timer]
-OnCalendar=*-*-* 03:15:00
+OnStartupSec=2min
+OnCalendar=*:0/15
 Persistent=true
-RandomizedDelaySec=30m
+RandomizedDelaySec=60s
+AccuracySec=30s
 Unit=nextcloud-borg-backup.service
 
 [Install]

systemd/user/nextcloud-borg-health.service

@@ -0,0 +1,9 @@
+[Unit]
+Description=Warn if verified Nextcloud NAS backup is overdue
+
+[Service]
+Type=oneshot
+ExecStart=%h/.local/bin/nextcloud-borg-backup health --notify
+TimeoutStartSec=45s
+UMask=0077
+NoNewPrivileges=true

systemd/user/nextcloud-borg-health.timer

@@ -0,0 +1,11 @@
+[Unit]
+Description=Hourly Nextcloud backup age watchdog
+
+[Timer]
+OnStartupSec=5min
+OnCalendar=hourly
+Persistent=true
+RandomizedDelaySec=2min
+
+[Install]
+WantedBy=timers.target