diff --git a/docs/content/blog/scaling_websocket.md b/docs/content/blog/scaling_websocket.md
index 92d47eea02..585961139f 100644
--- a/docs/content/blog/scaling_websocket.md
+++ b/docs/content/blog/scaling_websocket.md
@@ -74,6 +74,8 @@ conns.Add(conn)
 
 – otherwise you have a risk to not even able to look at `pprof` when things go bad. And you always need monitoring of open file descriptors.
 
+You can also consider using [netutil.LimitListener](https://godoc.org/golang.org/x/net/netutil#LimitListener) for this task, but don't forget to put pprof on another port with another HTTP server instance in this case.
+
 Keep attention on *Ephemeral ports* problem which is often happens between your load balancer and your WebSocket server. The problem arises due to the fact that each TCP connection uniquely identified in the OS by the 4-part-tuple:
 
 ```
diff --git a/docs/content/server/engines.md b/docs/content/server/engines.md
index 34667d3c24..f2fa670be7 100644
--- a/docs/content/server/engines.md
+++ b/docs/content/server/engines.md
@@ -192,6 +192,9 @@ When sharding enabled Centrifugo will spread channels and history/presence keys
 
 Redis cluster supported since Centrifugo v2.5.0
 
+!!!danger
+    Redis Cluster integration does not support `channels` API command due to Redis cluster limitations. Other Centrifugo features should work.
+
 Running Centrifugo with Redis cluster is simple and can be achieved using `redis_cluster_addrs` option. This is an array of strings. Each element of array is a comma-separated Redis cluster seed nodes. For example:
 
 ```json