Taming Microsoft Sentinel Costs Without Losing Detection

Begin with the decisions the logs support

Sentinel cost control starts with an inventory of the telemetry that supports detection, investigation, and retention obligations. Identify which sources drive active detections and which are used only occasionally. Storage changes should follow those uses rather than a blanket decision to move the largest tables.

Model the full cost

Microsoft documents Sentinel pricing and billing across ingestion, retention, and other applicable activities. Rates and entitlements depend on region, plan, commitment, and configuration. Use your current agreement and the official pricing calculator; historical per-gigabyte figures in the supplied draft are intentionally omitted because they are not a current quote.

Supporting reference: Plan costs and understand pricing and billing - Microsoft Sentinel ↗

Keep detection requirements visible

For each table, list the rules, queries, workbooks, automation, and investigative procedures that rely on it. Verify whether the proposed table plan or storage tier supports those uses before making a change. Lower-cost storage does not necessarily offer the same query behavior or detection capability.

Pilot a lower-cost path

Choose a bounded source and compare retrieval performance, query cost, retained detail, and investigator usability. Where supported, summary rules may provide compact derived data for recurring questions. Verify that the summary retains the information the detection actually requires and that the raw evidence remains available when needed.

Reduce waste without losing evidence

Review unnecessary columns, duplicate collection, and retention that exceeds a documented requirement. Use supported collection and transformation controls, test the result, and preserve the events needed for incident response. Do not discard a source merely because nobody queried it during a quiet month.

Make cost review an operating task

Track volume changes, query patterns, commitment utilization, and new dependencies after deployment. Assign an owner to exceptions and revisit the storage decision periodically. Savings should be demonstrated with the actual bill and validated coverage, not promised as a universal percentage.