diff --git a/apps/backup/README.md b/apps/backup/README.md
index d174b41..4665683 100644
--- a/apps/backup/README.md
+++ b/apps/backup/README.md
@@ -12,10 +12,10 @@ One-time host preparation for PostgreSQL: `sudo install -d -o 962 -g 962 -m 0700
 
 Each CephFS CronJob mounts one existing CephFS PVC read-only and mirrors it to its own pre-created bcachefs directory with `rsync --archive --numeric-ids --inplace --partial --delete`. It refuses to run unless `/source` is a CephFS mount and `/backup` is bcachefs. These are mirrors, so source deletions and changes propagate to the mirror; they do not provide historical snapshots.
 
-The RGW job syncs all 12 current buckets with `rclone sync`. It reads Rook-generated per-bucket object user Secrets in `rook-ceph`; the `nextcloud-new` bucket uses the existing `nextcloud` object user. The destination is a local mirror, and remote deletions propagate. The first complete CephFS and S3 runs are needed before declaring these data sets backed up.
+The RGW job syncs all 12 current buckets with `rclone sync`. It reads Rook-generated per-bucket object user Secrets in `rook-ceph`; the `nextcloud-new` bucket uses the existing `nextcloud` object user. The destination is a local mirror, and remote deletions propagate. The first complete CephFS and S3 runs are needed before declaring these data sets backed up. The combined S3 run has a 48-hour deadline because the buckets total roughly 527 GB; its CronJob forbids overlapping runs.
 
 ## Schedules and alerts
 
-PostgreSQL runs daily between 02:15 and 06:30 Europe/Vienna; CephFS mirrors run between 07:00 and 12:30; RGW starts at 13:00. The schedule staggers starts, but a long run can overlap a later one. Prometheus alerts on failed backup Jobs and any backup CronJob without a success in 25 hours. A missing `/mnt/backup` mount fails the pod setup or the in-container filesystem check and therefore cannot write into the underlying directory.
+PostgreSQL runs daily between 02:15 and 06:30 Europe/Vienna; CephFS mirrors run between 07:00 and 12:30; RGW starts at 13:00. CronJobs forbid overlapping runs of the same backup. Prometheus alerts on failed backup Jobs, daily backup CronJobs without a success in 25 hours, and the S3 mirror without a success in 48 hours. A missing `/mnt/backup` mount fails the pod setup or the in-container filesystem check and therefore cannot write into the underlying directory.
 
 Valkey/Redis persistence is not included yet. etcd and RBD remain deferred. Existing files and old scripts directly under `/mnt/backup` are preserved. No restore has been performed; the PostgreSQL archive checks validate archive readability, not a full restore rehearsal.
diff --git a/apps/backup/s3/resources.yaml b/apps/backup/s3/resources.yaml
index 305326b..5a65e9d 100644
--- a/apps/backup/s3/resources.yaml
+++ b/apps/backup/s3/resources.yaml
@@ -62,7 +62,7 @@ spec:
   jobTemplate:
     spec:
       backoffLimit: 0
-      activeDeadlineSeconds: 43200
+      activeDeadlineSeconds: 172800
       template:
         spec:
           nodeSelector:
diff --git a/apps/prometheus/resources/backup-alerts.yaml b/apps/prometheus/resources/backup-alerts.yaml
index 601f504..64d542e 100644
--- a/apps/prometheus/resources/backup-alerts.yaml
+++ b/apps/prometheus/resources/backup-alerts.yaml
@@ -22,13 +22,13 @@ spec:
             description: "{{ $labels.namespace }}/{{ $labels.job_name }} failed; inspect its pod logs and /mnt/backup mount."
         - alert: ScheduledBackupStale
           expr: |-
-            (time() - kube_cronjob_status_last_successful_time{cronjob=~".*backup.*"} > 90000)
+            (time() - kube_cronjob_status_last_successful_time{cronjob=~".*backup.*",cronjob!="s3-backup"} > 90000)
             or
             (
-              (kube_cronjob_info{cronjob=~".*backup.*"}
-                unless kube_cronjob_status_last_successful_time{cronjob=~".*backup.*"})
+              (kube_cronjob_info{cronjob=~".*backup.*",cronjob!="s3-backup"}
+                unless kube_cronjob_status_last_successful_time{cronjob=~".*backup.*",cronjob!="s3-backup"})
               and on(namespace,cronjob)
-              (time() - kube_cronjob_created{cronjob=~".*backup.*"} > 90000)
+              (time() - kube_cronjob_created{cronjob=~".*backup.*",cronjob!="s3-backup"} > 90000)
             )
           for: 10m
           labels:
@@ -36,3 +36,19 @@ spec:
           annotations:
             summary: "A scheduled backup has no recent successful run"
             description: "{{ $labels.namespace }}/{{ $labels.cronjob }} has not completed successfully in 25 hours."
+        - alert: S3BackupStale
+          expr: |-
+            (time() - kube_cronjob_status_last_successful_time{namespace="rook-ceph",cronjob="s3-backup"} > 172800)
+            or
+            (
+              (kube_cronjob_info{namespace="rook-ceph",cronjob="s3-backup"}
+                unless kube_cronjob_status_last_successful_time{namespace="rook-ceph",cronjob="s3-backup"})
+              and on(namespace,cronjob)
+              (time() - kube_cronjob_created{namespace="rook-ceph",cronjob="s3-backup"} > 172800)
+            )
+          for: 10m
+          labels:
+            severity: critical
+          annotations:
+            summary: "The S3 backup has no recent successful run"
+            description: "rook-ceph/s3-backup has not completed successfully in 48 hours."