This document provides recommendations for deploying Elasticsearch at large scale in a production environment. It covers topics such as cluster configuration, index structure, capacity planning, optimizing indexing throughput, searching, and testing. The key recommendations are to use unicast with seed nodes for the cluster, reduce the number of shards, implement time-based indices, perform capacity planning on production hardware, optimize indexing throughput using SSDs and adjusting bulk size, and always have a staging cluster to test changes.