I am experiencing a very strange behavoir at the moment. I have an eight-node cluster, cluster is up and running (status green), I can send search request and get responses, I can ask for cluster health and cluster state, and thats it. I dont get any answer on cluster nodes, stats, segments, nothing, no response. Last thing I did was writing 5m docs in two indices, that worked fine. Does anyone ever experienced something similar? Any hints what to do to get the cluster back responding (apart from restart)? Any idea what could be the reason for this?
Ok, after this seemed to be reproducable I looked around a bit more in several log files, it seems that something brought an optimization process to halt (on one node), blocking further optimizations. So whenever I try to optimize an index I will get the following exception and can not retrieve stats anymore: