Have you seen https://www.elastic.co/guide/en/elasticsearch/reference/current/disk-allocator.html#disk-allocator https://www.elastic.co/guide/en/elasticsearch/r

Have you seen https://www.elastic.co/guide/en/elasticsearch/reference/current/disk-allocator.html#disk-allocator https://www.elastic.co/guide/en/elasticsearch/reference/curr... ? Elasticsearch does take into account disk usage when balancing shards. Perhaps you haven't yet hit the (configurable) high water mark where that rebalancing would occur? I work for Elastic, but not on Elasticsearch.