diff --git a/_data/rules.yml b/_data/rules.yml
index da449ea..b2801b0 100644
--- a/_data/rules.yml
+++ b/_data/rules.yml
@@ -1134,7 +1134,7 @@ groups:
                 severity: warning
               - name: Ceph PG unavailable
                 description: Some Ceph placement groups are unavailable.
-                query: 'ceph_pg_total - ceph_pg_active > 0
+                query: 'ceph_pg_total - ceph_pg_active > 0'
                 severity: error
 
       - name: ZFS