An organization needs to move 200 TB of archival data to Azure but has a slow internet connection that would take months to upload. Which service is the best fit?

An appropriately sized Azure Data Box device. Azure Data Box supports large offline transfers when network upload is impractical. A currently orderable Data Box option with sufficient usable capacity may handle 200 TB; verify the destination region and device availability.

Which migration approach moves on-premises applications to Azure VMs without any code changes?

Rehost (lift and shift). Rehost, also called lift and shift, moves applications to Azure VMs as-is with no code modifications. Refactor makes minor changes for PaaS, rearchitect redesigns for cloud-native patterns, and rebuild starts from scratch.

A team is considering online migration of SQL Server to Azure SQL Managed Instance. What should it verify before promising a short cutover?

Current source-target and online-mode support, replication health, and a rehearsed cutover. DMS online migration may reduce downtime for supported source-target pairs, but no universal five-minute cutover is guaranteed. Validate the support matrix, replicate, test, and plan application cutover.

Azure Migration Services and Tools — Free Study Guide 2026

Quick Answer: Azure Migrate supports discovery, assessment, and migration planning for supported workloads. Azure Data Box supports large offline data transfers. Both are listed in the current AZ-900 migration objective. Database Migration Service and detailed migration strategies are useful implementation context, not named objectives. Costs and migration modes vary by scenario.

Azure Migrate: the central hub

Azure Migrate brings discovery, assessment, and supported server-migration workflows into one place. Its discovery and assessment features have no separate service charge, but projects may incur replication storage, network, test-compute, target-resource, or partner-tool charges. Use it when the source and target scenario is supported; the AZ-900 outline names its migration purpose without making it the starting point for every kind of migration. Depending on the source environment and feature, an appliance or connector can discover server inventory, utilization, and dependencies. Validate discovery coverage and data quality before sizing a migration.

What Azure Migrate covers

Tool inside Azure Migrate	What it does
Discovery and assessment	Inventories servers, checks Azure-readiness, recommends VM sizes
Server migration	Supports selected physical, virtual, and cloud-source scenarios; check current support and costs
Database assessment	Supported database tooling identifies compatibility and target options
Web app assessment	Evaluates ASP.NET/Java apps for Azure App Service
Azure Virtual Desktop assessment	Available planning scenarios depend on current product support

An assessment can report Azure-readiness, an Azure SKU recommendation, and a modeled monthly cost for supported workloads. Azure Migrate offers performance-based sizing when adequate performance history is available and as-is sizing based on provisioned capacity; inspect the selected assessment setting before interpreting a recommended VM size.

Azure Database Migration Service (DMS)

Azure Database Migration Service (DMS) supports specified source-to-target migrations; its mode and availability vary by pair. These details go beyond the current AZ-900 migration objective, which names Azure Migrate and Azure Data Box.

Source	Common Azure target
SQL Server	Selected Azure SQL Database, SQL Managed Instance, or SQL VM scenarios; online support differs by target
MySQL	Check supported Azure Database for MySQL migration scenario
PostgreSQL	Check supported Azure Database for PostgreSQL migration scenario
Other engines	Consult the current source-target support matrix before selecting DMS

Mode	Behavior	Downtime
Offline	Migrate with an application outage or controlled pause	Depends on data size and method
Online	Synchronize while source remains available, then plan cutover	Usually lower downtime, but no guaranteed duration

Worked example: A retailer wants to migrate SQL Server to Azure SQL Managed Instance while minimizing downtime. First verify that the source-target pair and online mode are supported, then test replication and rehearse cutover. Online migration can reduce downtime, but it cannot promise a five-minute window. A development copy may be moved offline if the outage is acceptable.

The Data Box family: offline transfer

When you must move tens of terabytes or more and your internet link is slow, copying over the wire could take weeks. Azure Data Box is the physical answer — Microsoft ships you a ruggedized, encrypted device, you copy data locally, and ship it back.

Device	Usable capacity	Typical use
Data Box Disk	Capacity depends on ordered disks and current availability	Smaller offline transfers
Data Box	Current options include about 120 TB or 525 TB usable; check regional catalog	Large offline transfers

Workflow: order in the portal, Microsoft ships it, you copy data over local SMB/NFS, ship it back, Microsoft uploads it to your storage account, then securely wipes the device to NIST standards.

Migration strategies — the 5 Rs

The following five labels are a useful planning vocabulary, not a claimed AZ-900 tested sequence. Actual migration strategy depends on workload, risk, time, and target architecture.

Rehost (lift and shift): move an application to Azure IaaS with little or no code change. It can shorten an initial move, but operational, compatibility, security, and cost risks still require assessment. Consider it when time is constrained and the existing architecture can run appropriately in Azure.
Refactor: make minor changes so the app runs on PaaS such as Azure App Service or Azure SQL Database. You shed some patching and server management without rewriting business logic.
Rearchitect: redesign the application for cloud-native patterns such as microservices, containers (Azure Kubernetes Service), or serverless (Azure Functions). Higher effort, higher long-term payoff.
Rebuild: discard the old code and build fresh as a cloud-native app.
Replace: retire the application entirely and adopt a SaaS product such as Dynamics 365 instead.

The Cloud Adoption Framework migration journey

A practical migration plan can be organized as assess, migrate, optimize, then operate securely. This is an editorial workflow, not a fixed Cloud Adoption Framework phase sequence or a published AZ-900 question pattern:

Phase	Key actions
Assess	Inventory workloads, map dependencies, build a modeled business case with Azure Migrate
Migrate	Choose a strategy (the 5 Rs), replicate, cut over, and validate
Optimize	Right-size VMs, apply Reserved Instances and Azure Hybrid Benefit, tier cold data
Secure and Manage	Turn on Microsoft Defender for Cloud, Azure Policy, monitoring, and backup

An Azure Migrate business case can model on-premises and Azure economics from assessment inputs, while the Pricing Calculator estimates planned Azure services. The TCO Calculator has been retired. Right-sizing during optimization may reduce cost. Confirm discovery coverage, assessment mode, and performance history before acting on a smaller-SKU recommendation.

On the Exam: "Large data, limited bandwidth, move to Azure" = Data Box. "Discover and assess on-premises servers" = Azure Migrate. For database migration, check the supported target and online/offline methods before selecting DMS. Rehosting means moving with minimal code change. For migration economics, use Azure Migrate business-case analysis; the current AZ-900 outline names Azure Migrate and Data Box.

Azure AZ-900

Azure Migration Services and Tools

Key Takeaways