Apache Solr is open source search software. It's capable of being implemented as an enterprise-level search engine thanks to its high scalability, advanced indexing, fast queries, and ability to integrate with a large variety of applications. It's capable of tackling big data and also has high availability with its load balancing and failover configurations.
This is a companion discussion topic for the original entry at https://linuxconfig.org/apache-solr-linux-install