The node.bandwidth.recovery.operator.factor setting in Elasticsearch controls the factor by which the estimated bandwidth for recovery operations is adjusted. This setting helps fine-tune the recovery process by allowing operators to influence the bandwidth estimation used during shard recovery.
- Default value: 1.0
- Possible values: Any positive float value
- Recommendation: Start with the default value and adjust based on observed recovery performance and network conditions
This setting acts as a multiplier for the estimated bandwidth used during recovery operations. A value greater than 1.0 increases the estimated bandwidth, potentially speeding up recoveries, while a value less than 1.0 decreases it, which can be useful in constrained network environments.
This setting is available in Elasticsearch 7.9 and later versions.
Example Usage
To change the node.bandwidth.recovery.operator.factor using the cluster settings API:
PUT _cluster/settings
{
"persistent": {
"node.bandwidth.recovery.operator.factor": 1.5
}
}
In this example, we're increasing the factor to 1.5, which could be beneficial in scenarios where the actual network bandwidth is higher than Elasticsearch's initial estimate. This might lead to faster recovery operations, but should be done cautiously to avoid overwhelming the network or nodes.
Common Issues and Misuses
- Setting the factor too high can lead to network congestion and potentially slower overall recovery times
- Very low values might unnecessarily slow down recoveries, even when sufficient bandwidth is available
- Frequent changes to this setting can make it difficult to establish consistent recovery performance baselines
Do's and Don'ts
- Do monitor recovery times and network utilization after changing this setting
- Do consider the impact on other cluster operations when adjusting recovery bandwidth
- Don't set extremely high values without understanding your network capacity
- Don't ignore other factors that affect recovery performance, such as disk I/O
- Do test changes in a non-production environment before applying to production clusters
Frequently Asked Questions
Q: How does changing node.bandwidth.recovery.operator.factor affect cluster stability?
A: While it doesn't directly impact stability, setting it too high could lead to network saturation, potentially affecting other cluster operations. Conversely, setting it too low might unnecessarily prolong recovery processes.
Q: Can this setting be different for each node in the cluster?
A: No, this is a cluster-wide setting. It applies uniformly to all nodes in the cluster.
Q: How often should I adjust this setting?
A: It's best to adjust this setting infrequently and only after careful observation. Frequent changes can make it difficult to establish performance baselines.
Q: Will increasing this value always speed up recoveries?
A: Not necessarily. While it may speed up recoveries in some cases, if set too high, it could lead to network congestion and potentially slower overall recovery times.
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_bytes_per_sec. It's important to consider the interplay between these settings when tuning recovery performance.
