Reduce replicas on cold data tier

Some indices on the cold data tier keep more replica shards than their access pattern typically needs. Each extra replica uses storage and cluster resources on rarely queried data.

Note

For a complete list of insights, refer to AutoOps insights.

Insight details

Field	Value
Component	Elasticsearch
Severity	Low
Scope	Node
Domains	replication, resource-utilization

Example: What you might see in AutoOps

The following is an example of what you might see when this insight is triggered. Real insights use live data and links from your deployment or cluster.

The number of replicas on some indices can be reduced on cold nodes

What was detected

There was 1 replica detected in cold data tier for the following indices: logs-prod-000045, logs-prod-000046.

Recommendations

Note

AutoOps shows different recommendations depending on how their conditions match your deployment or cluster.

Condition: Shown when replication factor exceeds cold tier threshold.

Confirm logs-prod-000045 is backed up, then set number_of_replicas to 0 on the cold tier with the action below (currently 1 replicas). Fewer replicas can increase search latency because fewer nodes serve reads.

						PUT logs-prod-000045/_settings
					{
  "index": {
    "number_of_replicas": 0
  }
}
		
	

Note

Requires the manage index privilege. Requires Elasticsearch 8.0.0 or later. This action changes cluster or index configuration.

Background and impact

Reducing the number of replicas for the cold tier can improve performance, save on storage costs, enhance indexing throughput and ensure cluster stability. This is because replicas introduce additional resource usage, which can negatively impact performance and stability.