How do i find the store type of elastic search index?

When I send the http request - http://://_settings , I don't get the store type of my index. I haven't set any store type for the cluster. But I want to know what the elasticcluster chose the store type for my cluster. I am using Ubuntu 12.04 machine and oracle jre 1.7.

its Hybrid (niofs/mmapfs). More details here - https://www.elastic.co/guide/en/elasticsearch/reference/current/index-modules-store.html.