knowledge/categories/apps/elasticsearch.md

Elasticsearch

Elasticsearch is a search engine based on the Lucene library. It provides a distributed, multitenant-capable full-text search engine with an HTTP web interface and schema-free JSON documents.

Tips

Calculate number of replicas

N >= R + 1

N : number of nodes R: Number of replicas

How to resolve unassigned shards

https://www.datadoghq.com/blog/elasticsearch-unassigned-shards/#reason-3-you-need-to-reenable-shard-allocation