🔭 Azure Migrate
The unified migration hub — discover, assess, and migrate servers, databases, and web apps to Azure
Table of Contents
- Azure Migrate Hub
- Azure Migrate Appliance
- Discovery and Assessment
- Dependency Analysis
- Azure Migrate: Server Migration
- Azure Database Migration Service (DMS)
- SQL Assessment Tools
- Common Exam Scenarios
Azure Migrate Hub
Azure Migrate is a centralised migration platform in the Azure portal that consolidates discovery, assessment, and migration tools from both Microsoft and ISV partners into a single experience. It does not perform migrations itself — it orchestrates and integrates the right tools for each workload type.
flowchart TD
subgraph HUB["Azure Migrate Hub"]
DISC["Discovery & Assessment\n(formerly Server Assessment)"]
SMIG["Azure Migrate: Server Migration\n(formerly Server Migration)"]
DMS["Azure Database Migration Service\n(DMS)"]
WEB["App Service Migration Assistant\n(web apps)"]
DATA["Azure Data Migration Assistant\n(DMA — SQL assessment)"]
ISV["ISV Partner Tools\n(Carbonite, Zerto, Movere…)"]
end
subgraph OnPrem["On-Premises Sources"]
VMW["VMware vSphere"]
HYP["Hyper-V"]
PHYS["Physical / Other Cloud"]
SQLDB["SQL Server"]
WEBAPP["IIS Web Apps"]
end
subgraph Azure["Azure Targets"]
AVM["Azure VMs"]
AVS["Azure VMware Solution"]
AZURESQL["Azure SQL / MI / SQL on VM"]
APPSERV["Azure App Service"]
AKS["AKS"]
end
OnPrem --> HUB --> Azure
Azure Migrate Appliance
The Azure Migrate appliance is a lightweight on-premises VM (VMware, Hyper-V, or physical) that performs agentless discovery and assessment — it does not require agents on individual source VMs.
| Property | Detail |
|---|---|
| Deployment | OVA template (VMware), VHD (Hyper-V), or installer script (physical) |
| Discovery | vCenter API for VMware; Hyper-V WMI; agent for physical |
| Data collected | VM inventory, CPU/memory/disk utilisation, network dependencies, installed apps |
| Communication | Appliance → Azure Migrate project (outbound HTTPS 443 only) |
| Max inventory | Up to 10,000 VMs per VMware appliance; 5,000 per Hyper-V |
| Continuous assessment | Sends performance data continuously for right-sizing |
Discovery and Assessment
Assessment Types
| Assessment | Target | Sizing Basis |
|---|---|---|
| Azure VM assessment | Azure VMs | As-on-premises or performance-based sizing |
| Azure VMware Solution (AVS) | AVS nodes | Maps VMs to AVS SKUs |
| Azure SQL assessment | Azure SQL DB / MI / SQL on VM | Compatibility + configuration analysis |
| Azure App Service assessment | Azure App Service | IIS app readiness |
| AKS assessment | AKS | Container readiness |
Sizing Strategies
| Strategy | Description | Best For |
|---|---|---|
| As on-premises | Maps current CPU/RAM directly to Azure VM size | Predictable workloads, compliance-driven sizing |
| Performance-based | Analyses 30+ days of utilisation data, right-sizes to actual usage | Cost-optimised migration |
⚠️ Exam Caveat — Performance-Based Sizing Requires Data Collection Period: Performance-based assessments require the appliance to collect utilisation data for a minimum of 1 day (recommended: 30 days) before generating a reliable sizing recommendation. If the scenario says “migrate immediately”, use as-on-premises sizing and right-size post-migration.
Dependency Analysis
Dependency analysis maps network connections between VMs to identify hidden dependencies before migration — prevents breaking communication paths.
| Mode | How It Works | Agent Required |
|---|---|---|
| Agentless | Captures TCP connection data via the appliance (VMware only) | ❌ No agents on source VMs |
| Agent-based | Installs Log Analytics Agent + Dependency Agent on each VM; uses Service Map | ✅ Agents on each VM |
| Feature | Agentless | Agent-based |
|---|---|---|
| Process-level details | ❌ | ✅ |
| Port-level details | ✅ (limited) | ✅ (full) |
| Cross-platform | VMware only | VMware, Hyper-V, Physical |
| Setup complexity | Low | Medium |
⚠️ Exam Caveat: Agentless dependency analysis is VMware-only. For Hyper-V or physical servers, agent-based dependency analysis is required.
Azure Migrate: Server Migration
Migrates VMs to Azure using replication — similar mechanism to ASR but optimised for one-time migration rather than ongoing DR.
| Source | Method |
|---|---|
| VMware (agentless) | vCenter snapshot-based replication via appliance |
| VMware (agent-based) | Mobility Service installed on each VM |
| Hyper-V | Azure Migrate agent on Hyper-V host |
| Physical / AWS / GCP | Mobility Service on each machine |
Migration Steps
flowchart LR
DISC["1. Discover\n(Appliance)"]
ASSESS["2. Assess\n(Right-size, cost)"]
REP["3. Replicate\n(Continuous replication starts)"]
TEST["4. Test Migration\n(Isolated VNet — no prod impact)"]
CUT["5. Cutover\n(Final sync, stop source, promote target)"]
CLEAN["6. Decommission\n(Remove source VMs)"]
DISC --> ASSESS --> REP --> TEST --> CUT --> CLEAN
⚠️ Exam Caveat — Test Migration Before Cutover: The Test Migration step spins up migrated VMs in an isolated VNet — without stopping source machines — allowing validation before the real cutover. This is a best-practice step the exam expects you to include in migration plans.
Azure Database Migration Service (DMS)
DMS migrates databases to Azure using online (continuous sync) or offline (one-time bulk load) modes, depending on the target. Not all targets support online migration — Azure SQL Database is offline only.
| Source | Target | Mode |
|---|---|---|
| SQL Server (on-prem / VM) | Azure SQL Database | Offline only ⚠️ |
| SQL Server (on-prem / VM) | Azure SQL Managed Instance | Online (CDC) + Offline |
| SQL Server (on-prem / VM) | SQL Server on Azure VM | Online + Offline |
| MySQL (on-prem) | Azure Database for MySQL | Online + Offline |
| PostgreSQL (on-prem) | Azure Database for PostgreSQL | Online + Offline |
| Oracle | Azure Database for PostgreSQL | Offline |
| MongoDB | Azure Cosmos DB (API for MongoDB) | Offline |
DMS SKUs
| SKU | Use Case | Online Migration |
|---|---|---|
| Standard (shared) | Small migrations, offline only | ❌ |
| Premium (dedicated) | Large databases, online (near-zero downtime) | ✅ |
⚠️ Exam Caveat — Azure SQL Database: Offline Only: Online (CDC) migration is not available for Azure SQL Database as a DMS target. Only offline migration is supported, which means application downtime starts when the migration begins. If the scenario requires near-zero downtime migration to Azure SQL Database, the answer is not DMS — instead, consider transactional replication or other third-party tools. If the scenario specifies Azure SQL Managed Instance with minimal downtime, the answer is DMS Premium (online/CDC mode).
⚠️ Exam Caveat — DMS (classic) Retired March 2026: DMS (classic) SQL Server scenarios were retired on March 15, 2026. The current recommended tool is the Azure SQL Migration extension for Azure Data Studio (powered by the newer DMS), which supports the same scenario matrix above.
SQL Assessment Tools
| Tool | Purpose |
|---|---|
| Data Migration Assistant (DMA) | Assess SQL Server compatibility, identify breaking changes, recommend target (SQL DB vs MI vs VM) |
| Database Experimentation Assistant (DEA) | Replay workload traces to measure performance on target |
| SQL Server Migration Assistant (SSMA) | Migrate non-SQL databases (Oracle, MySQL, Access, Sybase) to SQL Server or Azure SQL |
Common Exam Scenarios
| Scenario | Answer |
|---|---|
| Discover on-premises VMware estate without agents | Azure Migrate appliance (agentless) |
| Right-size Azure VMs based on actual usage | Azure Migrate assessment — performance-based sizing |
| Map dependencies between VMs before migration | Dependency analysis (agentless for VMware, agent-based for Hyper-V) |
| Migrate SQL Server to Azure SQL MI with minimal downtime | DMS Premium (online/CDC mode) |
| Migrate SQL Server to Azure SQL Database with minimal downtime | DMS only supports offline for SQL DB — consider transactional replication or plan for downtime |
| Assess SQL Server compatibility before migration | Data Migration Assistant (DMA) |
| Validate migrated VMs before cutting over production | Test Migration (isolated VNet) |
| Migrate Oracle database to Azure PostgreSQL | SSMA (SQL Server Migration Assistant) |
| Migrate IIS web apps to Azure App Service | App Service Migration Assistant |
| Migrate 5,000 VMware VMs at scale | Azure Migrate + agentless replication |