Introduction
There are currently two major open source search engine projects that are based on Lucene. They are Solr and Elasticsearch; both are very capable search engines and their search/indexing performance and features are comparable. Solr has a nicer admin user interface, while Elasticsearch provides a simpler RESTful interface for its entire API. Elasticsearch has more emphasis on sharding for distributed architecture, although Solr also provides SolrCloud, which is Solr's answer to the distributed architecture. At the time of writing, the latest Elasticsearch release is a stack of Elasticsearch, Logstash, and Kibana. Elasticsearch is becoming a big player in data analytics, providing capability to slice and dice time-series data (for example, logs analysis by Logstash) and visualization with Kibana.
Elasticsearch accepts data in JSON format. JSON is a widely accepted data format, you can read more about it here: http://www.json.org/. It also has the ability to be schema-less when...