Hi,
We have an unresponsive cluster that returns responses to /_status and /_cat/indices queries. It even responds to _nodes queries, but it does not respond to /_nodes/stats or any other query simply times out.
We noticed the degraded performance after we enabled Kibana 4 on our cluster, so we disabled Kibana and decided to upgrade our cluster to a bigger size. Unfortunately we are still unable to get any query to return a result.