Migration Assessment: Where to Start

You cannot migrate what you do not know

The most expensive mistake in cloud projects is starting to migrate before understanding what you have. A migration assessment turns uncertainty into a plan: it discovers workloads, maps dependencies, sizes the target and estimates cost. Without it, the project advances in the dark, with surprises in scope, cost and risk.

As a Microsoft Solutions Partner, RHC runs assessments with Azure Migrate and a structured method that precedes every migration.

What a good assessment answers

By the end, you should be able to answer:

1. What exists? A complete inventory of servers, VMs and applications.
2. How does it connect? A dependency map between systems.
3. How does it look at the target? Recommended sizing and SKU in Azure.
4. What does it cost? A monthly cost estimate with optimizations.
5. In what order? A wave roadmap prioritized by risk and value.

Discovery phase

Discovery collects real data, not assumptions:

• Inventory of operating systems, versions and configurations.
• Utilization metrics (CPU, memory, disk, network) over days or weeks to size on real usage, not theoretical peak.
• Applications and their business owners.
• Requirements for compliance, data residency and latency.

Azure Migrate performs this collection with or without agents, feeding the following phases.

Dependency map

Systems rarely live in isolation. Dependency mapping reveals:

• Which services communicate and on which ports.
• Which applications must migrate together to avoid cloud-to-source latency.
• Hidden integrations no one documented.

This map is what lets you design coherent waves in the migration.

Sizing and cost

With real utilization in hand, the assessment recommends the right target size:

Sizing on real usage and applying Azure Hybrid Benefit and reservations usually reduces the initial estimate significantly.

Readiness and strategy (6 Rs)

For each workload, the assessment evaluates readiness and recommends a strategy:

• Rehost for ready, low-risk workloads.
• Replatform for a quick gain with low effort.
• Refactor/Rebuild for strategic workloads.
• Replace with SaaS where the function is commoditized.
• Retire for what has no usage.

The result is a decision table that guides the effort for each workload.

The deliverable: an actionable roadmap

An assessment does not end in a shelf report. The useful deliverable includes:

1. Consolidated inventory and dependency map.
2. Per-application strategy (6 Rs).
3. Sizing and cost estimate with optimized scenarios.
4. Wave plan with sequence, dependencies and success criteria.
5. Risks and mitigations identified.
6. High-level landing zone design.

Mistakes an assessment prevents

• Over-sizing the target by mirroring current configuration.
• Breaking dependencies and creating latency between tiers.
• Underestimating timeline by not knowing the real complexity.
• Forgetting compliance and data residency.
• Migrating junk: moving systems that should be retired.

Key takeaways

• Never migrate without an assessment: it converts uncertainty into a plan.
• Base sizing on real utilization, not theoretical peak.
• Build the dependency map to design coherent waves.
• Apply Hybrid Benefit and reservations in the cost estimate itself.
• Deliver an actionable roadmap, not a shelf report.
• Use the assessment to retire what should not be migrated.

RHC runs the assessment with Azure Migrate and delivers a prioritized roadmap that reduces risk and cost before the first wave.