---
title: Enable Adaptive Replica Selection
description: Describes what AutoOps detects and surfaces with the Enable Adaptive Replica Selection insight: Adaptive replica selection is turned off on the cluster.
url: https://docs-v3-preview.elastic.dev/elastic/autoops-insights/tree/main/elasticsearch/enable_adaptive_replica_selection
products:
  - Elastic Cloud Enterprise
  - Elastic Cloud Hosted
  - Elastic Cloud on Kubernetes
  - Elasticsearch
applies_to:
  - Elastic Cloud Hosted: Generally available
  - Elastic Cloud on Kubernetes: Generally available
  - Elastic Cloud Enterprise: Generally available
  - Self-managed Elastic deployments: Generally available
---

# Enable Adaptive Replica Selection
Adaptive replica selection is turned off on the cluster. Coordinating nodes will not prefer faster or less loaded replica copies when executing searches.
<note>
  For a complete list of insights, refer to [AutoOps insights](https://docs-v3-preview.elastic.dev/elastic/autoops-insights/tree/main/elasticsearch).
</note>


## Insight details


| Field     | Value               |
|-----------|---------------------|
| Component | Elasticsearch       |
| Severity  | Medium              |
| Scope     | Cluster             |
| Domains   | performance, search |


## 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 adaptive replica selection setting is set to false/turned off


#### What was detected

_No description available._

#### Recommendations

<note>
  AutoOps shows different recommendations depending on how their conditions match your deployment or cluster.
</note>

<dropdown title="Enable adaptive replica selection">
  **Condition**: Always shown for this insight.Enable adaptive replica selection so Elasticsearch routes searches to less-loaded replicas. Use the action below.
  ```json

  {
    "persistent": {
      "cluster.routing.use_adaptive_replica_selection": true
    }
  }
  ```

  <note>
    Requires the `manage cluster` privilege. Requires Elasticsearch 8.0.0 or later. This action changes cluster or index configuration.
  </note>
</dropdown>


#### Background and impact

Impact: If adaptive replica selection is not enabled, search requests might not be properly load balanced, and a distressed node might delay responses.
Adaptive Replica Selection (ARS) allows each coordinating node to track the search latency of each data node, which informs the choice of which shard copies will participate in each search execution. This improves search latency and overall search throughput, and reduces the search load on already loaded data nodes.
ARS was introduced in ES 6.1 and is enabled by default in Version 7 and onwards.

### Guide

[Cluster level shard allocation routing settings](https://docs-v3-preview.elastic.dev/elastic/elasticsearch/tree/main/reference/elasticsearch/configuration-reference/cluster-level-shard-allocation-routing-settings)