Apache Solr is an open source enterprise search platform which is part of the Apache Lucene project. It is designed for rapid searching of data stored in HDFS in Apache Hadoop. Solr provides indexing, replication and load-balanced querying, a centralized configuration scheme, automated failover and recovery and is highly scalable, reliable and highly fault tolerant. Many of the Internet’s largest sites use Apache Solr for their search and navigation features. Solr's external configuration allows it to be tailored to many types of application without Java coding, and it has a plugin architecture to support more advanced customization.