Your organization uses Microsoft Sentinel to aggregate logs from on-premises and cloud sources. You need to reduce the cost of data ingestion while ensuring security-critical logs are retained for at least one year. What should you do?
Trap 1: Archive all logs to Azure Storage after 90 days
Archiving all logs to Azure Storage after 90 days moves them out of Sentinel's operational store, so you lose native KQL query, detection, and investigation capabilities. To analyze archived data, you must rebuild pipelines to re-ingest or use external tools, which adds latency and complexity. This approach cuts costs but fails to preserve the interactive security operations workflow that Sentinel is designed to provide.
Trap 2: Use the Basic logs tier for all logs and set retention to 365 days
Using the Basic logs tier for all logs with 365-day retention drastically limits the power available for security analysis. Basic tier supports only a subset of KQL operators and lacks features like functions, saved queries, and certain alerting scenarios, which are essential for threat detection and investigation. While it reduces cost, it would prevent you from performing the advanced analysis required for security-critical events, making it unsuitable as the sole tier for Sentinel workloads.
Trap 3: Set the default retention to 30 days and export logs to Log…
A default retention of 30 days is far below the required one-year period, so the environment would not meet compliance for long-term log access. Exporting to another Log Analytics workspace does not resolve this because the exported data is a copy, not a continuation of the original workspace, and it introduces duplicate storage costs and management overhead. Furthermore, the exported workspace lacks the seamless integration with Sentinel's incidents, alerts, and workbooks, making it an impractical workaround for a simple retention-extension need.
- A
Archive all logs to Azure Storage after 90 days
Why wrong: Archiving all logs to Azure Storage after 90 days moves them out of Sentinel's operational store, so you lose native KQL query, detection, and investigation capabilities. To analyze archived data, you must rebuild pipelines to re-ingest or use external tools, which adds latency and complexity. This approach cuts costs but fails to preserve the interactive security operations workflow that Sentinel is designed to provide.
- B
Ingress security-critical logs to the Analytics logs tier with 365-day retention, and other logs to the Auxiliary logs tier with shorter retention
This hybrid approach directly addresses the one-year retention requirement while optimizing cost. Security-critical logs reside in the Analytics tier, which supports full KQL, advanced hunting, detections, and 365-day retention, ensuring no loss of investigative power. The Auxiliary logs tier, introduced for verbose telemetry, offers lower ingestion cost and basic query functionality for non-critical data, letting you retain comprehensive logs without overpaying. This separation balances compliance, performance, and budget far better than a one-size-fits-all strategy.
- C
Use the Basic logs tier for all logs and set retention to 365 days
Why wrong: Using the Basic logs tier for all logs with 365-day retention drastically limits the power available for security analysis. Basic tier supports only a subset of KQL operators and lacks features like functions, saved queries, and certain alerting scenarios, which are essential for threat detection and investigation. While it reduces cost, it would prevent you from performing the advanced analysis required for security-critical events, making it unsuitable as the sole tier for Sentinel workloads.
- D
Set the default retention to 30 days and export logs to Log Analytics Workspace
Why wrong: A default retention of 30 days is far below the required one-year period, so the environment would not meet compliance for long-term log access. Exporting to another Log Analytics workspace does not resolve this because the exported data is a copy, not a continuation of the original workspace, and it introduces duplicate storage costs and management overhead. Furthermore, the exported workspace lacks the seamless integration with Sentinel's incidents, alerts, and workbooks, making it an impractical workaround for a simple retention-extension need.