When a data index is created in Elasticsearch, the data is divided into shards for horizontal scaling across multiple nodes. These shards are small pieces of data that make up the index and play a significant role in the performance and stability of Elasticsearch deployments. A shard can be classified as either a primary shard or a replica shard. A replica is a copy of the primary shard, and whenever Elasticsearch indexes data, it is first indexed to one of the primary shards.

Whenever we start a search consulting project from scratch, the obvious question is: which search engine to use? We’ve talked about Elasticsearch vs Solr before, but here we’ll compare Elasticsearch with its fork, OpenSearch. Chances are, if you need to decide between the two, you’ll be looking at a few dimensions.

Businesses that have mission-critical applications deployed on servers often have operations teams dedicated to monitoring, maintaining, and ensuring the health and performance of these servers. Having a server monitoring system in place is critical, as well as monitoring the right parameters and following best practices. In this article, I’ll look at the key server monitoring best practices you should incorporate into your operations team’s processes to eliminate downtime.

Elasticsearch (ES) is a powerful tool offering multiple search, content, and analytics capabilities. You can extend its capacity and relatively quickly horizontally scale the cluster by adding more nodes. When data is indexed in some Elasticsearch index, the index is not typically placed in one node but is spread across different nodes such that each node contains a “shard” of the index data. The shard (called primary shard) is replicated across the cluster into several replicas.

Disk-related issues with Elasticsearch can present themselves through various symptoms. It is important to understand their root causes and know how to deal with them when they arise. As an Elasticsearch cluster administrator, you are likely to encounter some of the following cluster symptoms.