How many shards should I have in my Elasticsearch cluster?
Elasticsearch is a very versatile platform that supports a variety of use cases and provides great flexibility around data organisation and replication strategies. This flexibility can, however, sometimes make it hard to determine up-front how to best organize your data into indices and shards, especially if you are new to the Elastic Stack. While suboptimal choices will not necessarily cause problems when first starting out, they have the potential to cause performance problems as data volumes grow over time. The more data the cluster holds, the more difficult it also becomes to correct the problem, as reindexing of large amounts of data can sometimes be required.