If you’re working with time series data, you don’t want to continually dump everything into a single index. Instead, you might periodically roll over the data to a new index to keep it from growing so big it’s slow and expensive. As the index ages and you query it less frequently, you’ll likely move it to less expensive hardware and reduce the number of shards and replicas.
To automatically move an index through its lifecycle, you can create a policy to define actions to perform on the index as it ages. Index lifecycle policies are especially useful when working with Beats data shippers, which continually send operational data, such as metrics and logs, to Elasticsearch. You can automate a rollover to a new index when the existing index reaches a specified size or age. This ensures that all indices have a similar size instead of having daily indices where size can vary based on the number of Beats and the number of events sent.
Kibana’s Index Lifecycle Policies walks you through the process for creating and configuring a policy. Before using this feature, you should be familiar with index lifecycle management: