Cloud-Native SIEM for a Microsoft Estate

For an organisation already deep in Microsoft — Entra, Microsoft 365, Azure, Defender — the SIEM decision has a natural gravitational pull toward Microsoft Sentinel, the cloud-native security-information-and-event-management platform built to sit inside that ecosystem. That pull is real and often right, but “we’re a Microsoft shop, so Sentinel” is a starting hypothesis, not a finished decision. The integration advantages are genuine; so are the questions of cost, coverage of your non-Microsoft estate, and whether the platform meets your specific regulatory logging duties. Choosing Sentinel deliberately, rather than defaulting to it, is what turns the ecosystem fit into an actual advantage.

The case for Sentinel in a Microsoft estate

Sentinel’s strength in a Microsoft-centric organisation is integration. It connects natively to the Microsoft security stack — Defender, Entra, the Microsoft 365 and Azure logs — so much of your estate’s security telemetry flows in without the connector engineering a third-party SIEM would require. It is cloud-native, so there is no infrastructure to run, and it scales with your usage. And it is licensed and managed within the Microsoft world you already operate, which simplifies procurement and administration. For a firm whose estate is mostly Microsoft, this integration and operational simplicity is a real advantage, and it is why Sentinel is frequently the right answer for these organisations.

The questions that still need asking

• What does it cost at your data volume? Cloud-native SIEM prices on data ingestion, and comprehensive logging — especially the volume that DORA-style duties imply — drives that up. Model the cost at the data volume you actually need to log, not the pilot’s, because the licensing surprise is the same trap here as with any SIEM.
• Does it cover your non-Microsoft estate? Few organisations are purely Microsoft. How well Sentinel ingests and correlates the logs from your non-Microsoft systems — legacy, specialist, other clouds — often decides whether it is genuinely sufficient or leaves gaps.
• Does it meet your regulatory logging duties? Under DORA or NIS2, your SIEM has to support the detection, retention and reporting those regimes expect; confirm Sentinel does for your obligations, not in general.
• Do you have the capability to run it? Cloud-native does not mean self-running; Sentinel still needs configuration, tuning and monitoring, whether in-house or managed.

Deciding well

• Treat the Microsoft fit as a strong hypothesis, then test it. The ecosystem advantage is real, but confirm cost, coverage and compliance fit before defaulting.
• Model the data-volume cost honestly. The compliant logging volume, priced at Sentinel’s ingestion model, is the number that decides the economics.
• Check the non-Microsoft coverage. Your security depends on seeing the whole estate; verify Sentinel covers the parts that are not Microsoft.
• Confirm the regulatory fit specifically. Map your DORA or NIS2 logging duties to what Sentinel actually delivers for you.

For a Microsoft-centric organisation, Sentinel is frequently the pragmatic and powerful SIEM choice, and the native integration is a genuine advantage worth having. The discipline is to choose it on a tested fit — cost at your data volume, coverage of your whole estate, and your specific regulatory duties — rather than on the ecosystem pull alone. Done that way, the Microsoft fit becomes a real advantage; assumed rather than tested, it can hide a cost or coverage gap that surfaces after the platform is embedded.

Who this is for

This reading is for:

• CISOs and security architects in Microsoft-centric organisations
• Firms weighing Microsoft Sentinel against a standalone SIEM
• Compliance leads needing SIEM under DORA or NIS2 logging duties
• Boards approving a security-monitoring platform decision

Sixteen Pillars helps Microsoft-centric firms test the Sentinel fit – cost at their data volume, non-Microsoft coverage, and specific regulatory duties – rather than defaulting to it. Pricing is published at /pricing/. If this is live for your organisation and you would like an independent reading, the place to start is a conversation.

Sixteen Pillars is a technology governance consultancy based in Cyprus. Engagements run remote across the EU, UK, and Middle East, with on-site time where the engagement requires it.