Understanding Metrics Billing and Reducing Costs

Overview

Metrics billing is based on cardinality - the number of unique time series created by your metrics. Understanding how attributes affect cardinality is key to managing costs effectively.

How Attributes Affect Billing

There are two types of attributes that affect your metrics differently:

1. Identifying attributes - These create new time series and contribute to cost. For example, adding a new host.name creates a new series.
2. Non-identifying/descriptive attributes - These enrich existing metrics without creating new series. Examples include host family or EC2 tags.

You can add as many non-identifying attributes as needed without additional cost, but each new identifying attribute with unique values increases your bill, often exponentially.

Common Cost Drivers

High Cardinality Attributes

Avoid including random IDs or unique identifiers in your metric attributes. For example, instead of:

/bitcoin-mainnet-esplora/scripthash/20fd0a38027a2eeb14fd50fcbd94934f832bef4cc279958c30c72704338eb065/txs

Use a templated approach:

/bitcoin-mainnet-esplora/scripthash/${id}/txs

Histogram Metrics

Histogram metrics are particularly costly because:

1. Bucket configuration - Each bucket distribution creates a separate series. Optimize your bucket configuration based on your workload's latency patterns.
2. Cumulative nature - With cumulative histogram metrics, values continue to be sent even when there's no recent activity, especially problematic when combined with high-cardinality attributes like method names containing IDs.

Cost Reduction Strategies

1. Remove or Template High-Cardinality Attributes

Replace unique IDs with templated values to reduce the number of unique time series being created.

2. Optimize Histogram Buckets

Reduce the number of buckets while maintaining meaningful data. See Configure Custom Buckets for more details.

3. Implement Sampling

Reduce the volume of metrics sent from your application. This directly reduces the number of data points ingested.

4. Review Attribute Necessity

Ensure all identifying attributes are essential for your monitoring needs. Remove any attributes that don't provide actionable insights.

5. Aggregate or Drop Metrics

Consider using the following techniques:

• Aggregate labels - Use the MetricsTransform Processor to aggregate metrics, which actually reduces cardinality and sample count.
• Drop entire metrics - See How to Drop and Filter OpenTelemetry Metrics to remove unnecessary metrics entirely.

Monitoring Your Costs

Use the Cost Meter to:

• Monitor costs across different telemetry signals
• Understand the cost breakdown and key contributors
• Track metric datapoint ingestion over time
• Set up alerts to notify you when costs exceed thresholds

Additional Resources

• Comprehensive guide on cardinality
• Dropping Metric Labels - Why dropping labels doesn't reduce costs
• Cost Meter Overview - Monitor your observability costs