Estimating the Size of the M365 Advanced Tables for Microsoft Sentinel Enablement

The Microsoft 365 Defender Connector in Microsoft Sentinel is coming along nicely with all the table sources now available to select. The Connector is still in public preview, but the progress is a very welcome sight.

All the logs

Even though ingesting the M365 Advanced logs is considered necessary, enabling them will cost something.

There are two primary data costs to Microsoft Sentinel and those are ingestion and retention. A Microsoft Sentinel environment gets 90 days of free retention for active data and there are methods and approaches to managing the data once it hits the 90-day threshold.

The cost that will have the most immediate effect on the M365 Advanced logs is ingestion. And, rightfully so, getting an estimation of the volume and cost of enabling the Advanced logs is important.

Here’s a KQL query you can use at in the Advanced Hunting blade to get the average EPS and estimated GB for your environment.

let bytes_ = 500;
union withsource=MDTables*
| where Timestamp > startofday(ago(1d))
| summarize count() by bin(Timestamp, 1m), MDTables
| extend EPS = count_ /60
|summarize avg(EPS), estimatedGBytes = (avg(EPS) * bytes_ ) / (1024*1024*1024) by MDTables
| sort by toint(estimatedGBytes) desc

Run the query in Advanced Hunting in the Microsoft 365 Defender console

Once you have the EPS and estimated GBs, you can plug them into the Microsoft Sentinel calculator.

Microsoft Sentinel pricing information

Microsoft Sentinel calculator

Are you a Microsoft 365 E5, A5, F5, and G5, and Microsoft 365 E5, A5, F5, and G5 Security customer? Even for these Advanced logs you are eligible to receive a data grant of up to 5MB per user per day to ingest Microsoft 365 data.



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