monitoring: fix prometheus alert for full pools

The existing alert (introduced via
https://tracker.ceph.com/issues/24977) already triggers when still 50%
of storage space are available.

Fixes: https://tracker.ceph.com/issues/42982
Signed-off-by: Thomas Kriechbaumer <thomas@kriechbaumer.name>

diff --git a/monitoring/prometheus/alerts/ceph_default_alerts.yml b/monitoring/prometheus/alerts/ceph_default_alerts.yml
index 2f4560e0346bfa8578dbf973344110e24e904365..872be5cde744e3c32eb3996cee826272bdbabe9c 100644 (file)
--- a/monitoring/prometheus/alerts/ceph_default_alerts.yml
+++ b/monitoring/prometheus/alerts/ceph_default_alerts.yml
@@ -151,7 +151,7 @@ groups:
   - name: pools
     rules:
       - alert: pool full
-        expr: ceph_pool_stored / ceph_pool_max_avail * on(pool_id) group_right ceph_pool_metadata > 0.9
+        expr: ceph_pool_stored / (ceph_pool_stored + ceph_pool_max_avail) * on(pool_id) group_right ceph_pool_metadata > 0.9
         labels:
           severity: critical
           type: ceph_default