Microsoft Security Operations AnalystMitigate threats using Microsoft SentinelHard

A security engineer is tasked with optimizing the cost of Microsoft Sentinel. The current ingestion rate is 100 GB per day, and the organization has a commitment tier of 50 GB per day. Any data ingested beyond the commitment tier is billed at a pay-as-you-go rate. The engineer observes that a significant portion of the ingested data consists of verbose debug logs from non-critical applications that are rarely used for security investigations. What is the most effective strategy to reduce Sentinel ingestion costs related to these specific logs?

  1. AUse Azure Data Explorer to store the debug logs instead of Sentinel.
  2. BIncrease the commitment tier to match the current ingestion rate.
  3. CApply data transformation to filter out the verbose debug logs before ingestion.
  4. DChange the retention period for the debug logs to a shorter duration.
Show answer & explanation

Correct answer: C. Apply data transformation to filter out the verbose debug logs before ingestion.

Data transformation allows filtering out irrelevant data (like verbose debug logs) *before* it is ingested into Log Analytics/Sentinel. This directly reduces the volume of billed ingestion, which is the most effective way to reduce costs for unnecessary data.

Why the other options are wrong

  • A. Using Azure Data Explorer would shift the storage cost but not reduce the ingestion cost into Sentinel, or it would require a separate analytics solution, not optimizing Sentinel itself.
  • B. Increasing the commitment tier would reduce the pay-as-you-go rate for the excess, but not eliminate the cost of ingesting unnecessary data.
  • D. Changing retention affects storage costs, not ingestion costs. The data is already ingested and billed.

Microsoft Sentinel Cost Optimization - Ingestion

Optimizing Sentinel ingestion costs involves reducing the volume of data sent to Log Analytics. This can be achieved by filtering irrelevant data at the source or using ingestion-time transformations.

  • Billed primarily on data ingestion volume.
  • Commitment tiers offer discounted rates for predictable usage.
  • Filter out unnecessary data *before* ingestion to save most effectively.

Memory trick: Filter First, Then Fund Savings

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