Which version of Graylog are you using?
Which version of Elasticsearch are you using?
How did you install Graylog?
How did you install Elasticsearch?
What’s the index configuration (number of primary and replica shards)?
Which version of Graylog are you using : 2.2.3
Which version of Elasticsearch are you using : 2.x
How did you install Graylog : with this procedure : http://docs.graylog.org/en/2.2/pages/installation/os/ubuntu.html
How did you install Elasticsearch : Same that Graylog
What’s the index configuration (number of primary and replica shards) : 3 shard