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Settings

Shard indexing backpressure adds several settings to the standard OpenSearch cluster settings. They are dynamic, so you can change the default behavior of this feature without restarting your cluster.

High-level controls

The high-level controls allow you to turn the shard indexing backpressure feature on or off.

Setting Default Description
shard_indexing_pressure.enable False Change to true to enable shard indexing backpressure.
shard_indexing_pressure.enforced False Run shard indexing backpressure in shadow mode or enforced mode. In shadow mode (value set as false), shard indexing backpressure tracks all granular-level metrics, but it doesn’t actually reject any indexing requests. In enforced mode (value set as true), shard indexing backpressure rejects any requests to the cluster that might cause a dip in its performance.

Node-level limits

Node-level limits allow you to control memory usage on a node.

Setting Default Description
shard_indexing_pressure.primary_parameter.node.soft_limit 70% Define the percentage of the node-level memory threshold that acts as a soft indicator for strain on a node.

Shard-level limits

Shard-level limits allow you to control memory usage on a shard.

Setting Default Description
shard_indexing_pressure.primary_parameter.shard.min_limit 0.001d Specify the minimum assigned quota for a new shard in any role (coordinator, primary, or replica). Shard indexing backpressure increases or decreases this allocated quota based on the inflow of traffic for the shard.
shard_indexing_pressure.operating_factor.lower 75% Specify the lower occupancy limit of the allocated quota of memory for the shard. If the total memory usage of a shard is below this limit, shard indexing backpressure decreases the current allocated memory for that shard.
shard_indexing_pressure.operating_factor.optimal 85% Specify the optimal occupancy of the allocated quota of memory for the shard. If the total memory usage of a shard is at this level, shard indexing backpressure doesn’t change the current allocated memory for that shard.
shard_indexing_pressure.operating_factor.upper 95% Specify the upper occupancy limit of the allocated quota of memory for the shard. If the total memory usage of a shard is above this limit, shard indexing backpressure increases the current allocated memory for that shard.

Performance degradation factors

The performance degradation factors allow you to control the dynamic performance thresholds for a shard.

Setting Default Description
shard_indexing_pressure.secondary_parameter.throughput.request_size_window 2,000 The number of requests in the sampling window size on a shard. Shard indexing backpressure compares the overall performance of requests with the requests in the sample window to detect any performance degradation.
shard_indexing_pressure.secondary_parameter.throughput.degradation_factor 5x The degradation factor per unit byte for a request. This parameter determines the threshold for any latency spikes. The default value is 5x, which implies that if the latency shoots up 5 times in the historic view, shard indexing backpressure marks it as a performance degradation.
shard_indexing_pressure.secondary_parameter.successful_request.elapsed_timeout 300000 ms The amount of time a request is pending in a cluster. This parameter helps identify any stuck-request scenarios.
shard_indexing_pressure.secondary_parameter.successful_request.max_outstanding_requests 100 The maximum number of pending requests in a cluster.