Add logging docs to monitoring.

docs/engine-features.md

@@ -20,6 +20,7 @@ This page gives a more detailed overview of the Aura Engine features and how to
         - [Send mails on errors and warnings](#send-mails-on-errors-and-warnings)
         - [Engine Status Information](#engine-status-information)
         - [Engine Heartbeat](#engine-heartbeat)
+        - [Logging](#logging)
     - [Read more](#read-more)
 
 <!-- /TOC -->
@@ -196,6 +197,7 @@ You have following options to monitor the Engine:
 * Send mails on errors and warnings
 * Engine Status Information
 * Engine Heartbeat
+* Logging
 
 ### Send mails on errors and warnings
 
@@ -247,6 +249,24 @@ One scenario could be switching to another Engine instance or any other failover
 Under `contrib/heartbeat-monitor` you'll find some sample application digesting these
 heartbeat signals.
 
+### Logging
+
+In development all Engine logs can be found under `./log`, and for production they can
+are located in `/var/log/aura`. Adapt the log-level within your configuration to get
+more or less verbose log output:
+
+```ini
+logdir="/var/log/aura"
+
+# Possible values: debug, info, warning, error, critical
+loglevel="info"
+```
+
+The log directory holds individual logs from Engine Core, Liquidsoap and the API.
+But also `stout` outputs from supervisor services are written there.
+
+Additionally you'll finde Supervisor specific logs under`/var/log/supervisor`.
+
 
 
 ## Read more