Adjust NodeFilesystemFullSoon alert

* Remove 4 hour prediction because it is too sensitive.
* Replace with 12 hour prediction.

alerts/githost.rules

@@ -11,16 +11,16 @@ ALERT NodeFilesystemFullSoon
     runbook = "troubleshooting/filesystem_alerts.md",
   }
-# Use 1 hour of history to predict 4 hours into the future.
+# Use 12 hours of history to predict 48 hours into the future.
 ALERT NodeFilesystemFullSoon
-  IF predict_linear(node_filesystem_avail{fstype=~"ext.|xfs",mountpoint!~"/mnt/(backup-block-for|remote).*"}[1h], 4*60*60) < 0
-  FOR 10m
+  IF predict_linear(node_filesystem_avail{fstype=~"ext.|xfs",mountpoint!~"/mnt/(backup-block-for|remote).*"}[12h], 48*60*60) < 0
+  FOR 4h
   LABELS {
     severity = "crit",
   }
   ANNOTATIONS {
     summary = "Filesystem is filling up",
-    description = "Filesystem '{{ $labels.mountpoint }}' on {{ $labels.instance }} is filling up and will be full in the next 4 hours",
+    description = "Filesystem '{{ $labels.mountpoint }}' on {{ $labels.instance }} is filling up and will be full in the next 48 hours",
     runbook = "troubleshooting/filesystem_alerts.md",
   }