The indices.recovery.max_concurrent_snapshot_file_downloads_per_node setting in Elasticsearch controls the maximum number of concurrent file downloads allowed per node during snapshot recovery operations. This setting helps manage the resource utilization and network bandwidth consumption during the recovery process.
- Default value: 5
- Possible values: Any positive integer
- Recommendation: The default value is suitable for most scenarios, but it can be adjusted based on available resources and recovery performance requirements.
This setting limits the number of simultaneous file downloads that can occur on a single node when recovering from a snapshot. It helps prevent overwhelming the node's resources and network capacity during the recovery process.
Example
To change the value of this setting using the cluster settings API:
PUT _cluster/settings
{
"persistent": {
"indices.recovery.max_concurrent_snapshot_file_downloads_per_node": 10
}
}
Increasing this value can potentially speed up snapshot recovery operations by allowing more concurrent file downloads. However, it may also increase the load on the node and network resources. Consider adjusting this setting if you have high-performance hardware and network infrastructure, and you want to optimize recovery speed.
Common Issues and Misuses
- Setting the value too high can lead to excessive resource consumption and potentially slow down other operations on the node.
- Setting the value too low may unnecessarily prolong the recovery process, especially for large snapshots or when recovering multiple indices simultaneously.
Do's and Don'ts
- Do monitor node performance and network utilization when adjusting this setting.
- Do consider the available hardware resources and network capacity when increasing the value.
- Don't set this value excessively high without proper testing and monitoring.
- Don't forget to adjust related settings like
indices.recovery.max_concurrent_file_chunksfor optimal performance.
Frequently Asked Questions
Q: How does this setting affect snapshot recovery performance?
A: This setting directly impacts the speed of snapshot recovery by controlling the number of concurrent file downloads. A higher value can potentially speed up recovery but may also increase resource usage.
Q: Can changing this setting impact other cluster operations?
A: Yes, increasing this value can lead to higher resource utilization on the node, potentially affecting other ongoing operations. It's important to monitor overall cluster performance when adjusting this setting.
Q: Is it safe to change this setting on a production cluster?
A: While it's generally safe to adjust this setting, it's recommended to test changes on a staging environment first and monitor the impact closely when applying to production.
Q: How does this setting interact with other recovery-related settings?
A: This setting works in conjunction with other recovery settings like indices.recovery.max_concurrent_file_chunks. It's important to consider these related settings when optimizing recovery performance.
Q: Should this setting be adjusted for all nodes in the cluster?
A: It's generally recommended to apply this setting cluster-wide for consistency. However, if you have nodes with varying capabilities, you might consider node-specific settings.
