service/prometheus.md

@@ -2889,6 +2889,9 @@ would still be able to deduce some activity patterns from the metrics
 generated by Prometheus, and use it to leverage side-channel attacks,
 which is why the external Prometheus server access is restricted.
 
+Alerts themselves are retained in the systemd journal, see [Checking
+alert history](#checking-alert-history).
+
 ## Backups
 
 Prometheus servers should be fully configured through Puppet and