Have you followed the [instructions in the documentation](https://www.elastic.co/guide/en/elasticsearch/reference/5.6/tune-for-indexing-speed.html#tune-for-indexing-speed), especially around increasing the refresh_interval? Do you have X-Pack monitoring installed?

---
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB