Design infrastructure solutions · Topic 7 of 10
Migrating Workloads, Databases and Data
AZ-305 migration tools: Azure Migrate server migration, Database Migration Service, online versus offline moves, Data Box, AzCopy and Storage Mover.
- 5 min
- Azure Migrate Server Migration replicates then cuts over, with test migrations for validation.
- DMS supports online (minimal downtime) and offline migrations. Assess with Data Migration Assistant or Azure Migrate first.
- AzCopy is for one off and small transfers. Storage Mover orchestrates file migrations. Data Box is the offline option.
What it is
After planning, you pick tools to move three kinds of things: servers and applications, databases and unstructured data. Each has Azure services built for it, and a key design choice is online versus offline movement: online keeps systems running with minimal downtime, and offline ships data physically when the network is too slow.
How it works
Migrating workloads to IaaS and PaaS
| Source | Tool and target |
|---|---|
| VMware, Hyper-V, physical, AWS and GCP servers to Azure VMs | Azure Migrate: Server Migration. VMware has agentless replication with the appliance, or an agent based method. Replicates continuously, then you cut over with a short outage |
| Web apps to App Service | Azure App Service migration assistant and Azure Migrate web app assessment and migration |
| Containers and Kubernetes apps | Azure Migrate app containerization, or move images to ACR and deploy to AKS or Container Apps |
| VMware environments as is | Azure VMware Solution keeps the VMware stack with minimal change |
| Virtual desktops | Azure Virtual Desktop, with Azure Migrate for the session hosts |
| Disaster recovery based move | Azure Site Recovery can also move VMs between regions or from on premises |
Migrations follow replicate, test migration, cut over, clean up. A test migration creates an isolated copy to validate the application before the real cutover. Use Azure Hybrid Benefit and right size VMs after moving.
Migrating databases
| Source | Target | Tool |
|---|---|---|
| SQL Server | Azure SQL Database, SQL Managed Instance, SQL Server on VMs | Azure Database Migration Service (DMS), Azure Migrate, Data Migration Assistant for assessment, and for MI the Managed Instance link and log replay service |
| PostgreSQL and MySQL | Azure Database for PostgreSQL or MySQL flexible server | DMS and native tools |
| Oracle | Azure Database for PostgreSQL, or Oracle Database@Azure | Migration tools and the Oracle assessments |
| MongoDB | Cosmos DB for MongoDB | DMS or native tools |
Online migration continuously syncs changes until cutover, giving minimal downtime. Offline migration takes the database offline during the copy and suits maintenance windows and smaller databases. Choose online for large, busy, mission critical databases that cannot tolerate long downtime. Always run an assessment first to find compatibility blockers and the right target and tier. For SQL Server moving to Managed Instance with minimal downtime, the Managed Instance link replicates near real time and allows a controlled cutover.
Migrating unstructured data
| Tool | Fit |
|---|---|
| AzCopy | Command line copy to and from Blob and Files. Good for one off transfers and data under about 1 TB. No built in state tracking or error handling, so review logs and retry |
| Azure Storage Mover | A managed service that orchestrates file migrations from on premises to Azure Storage with agents and a central dashboard, and can run repeated syncs |
| Azure Data Box family | Offline transfer using physical devices, for large data over slow or costly links |
| Azure Data Box Gateway | A virtual appliance for continuous, one way transfer of data to Azure |
| Azure File Sync | Syncs on premises file servers with Azure Files and tiers cold data |
| Azure Data Factory | Scheduled copy and transformation between many sources |
| Object replication | Between storage accounts |
Data Box products include Data Box Disk (small SSDs, BitLocker encrypted, copy by SMB) and the Data Box appliance for tens to hundreds of terabytes, with larger and newer models for the biggest volumes, so check the current lineup. Only Data Box supports offline transfer. Choose it when copying over the network is too slow, too costly or impossible. A common pattern is offline seeding: ship the bulk with Data Box, then use an online tool to sync deltas until cutover. Use bandwidth estimates: if a transfer would take weeks, ship devices.
Choosing quickly
| Requirement | Answer |
|---|---|
| Move 200 VMware VMs with a short cutover | Azure Migrate Server Migration |
| Migrate a busy SQL Server with minimal downtime | DMS online migration, or the Managed Instance link |
| Copy 500 TB over a slow link | Azure Data Box |
| Repeated sync of an on premises file share to Azure Storage | Azure Storage Mover |
| One off copy of 200 GB to Blob | AzCopy |
| Keep the VMware stack unchanged in Azure | Azure VMware Solution |
A worked scenario
A manufacturer moves 150 VMs, a 3 TB SQL Server and 400 TB of engineering files. The architect uses Azure Migrate Server Migration with test migrations and short cutover windows. The SQL Server moves to Managed Instance with an online DMS migration so downtime is minutes. The 400 TB goes first on Data Box devices, and Storage Mover syncs the changes made since shipping until cutover.
What to remember for the exam
- Azure Migrate Server Migration replicates then cuts over, with test migrations for validation.
- DMS supports online (minimal downtime) and offline migrations. Assess with Data Migration Assistant or Azure Migrate first.
- AzCopy is for one off and small transfers. Storage Mover orchestrates file migrations. Data Box is the offline option.
- Offline seeding with Data Box plus online delta sync is a common pattern.
- Azure VMware Solution keeps VMware workloads unchanged.
"Large dataset, slow network" is Data Box. "Minimal downtime database move" is an online DMS migration.
How the exam asks about this
- "Move a busy database with minimal downtime." Online migration with DMS.
- "Transfer 300 TB from a site with a slow link." Azure Data Box.
- "Replicate on premises file shares to Azure Storage regularly." Azure Storage Mover.
- "Validate a VM migration before cutover." A test migration in Azure Migrate.
Common mistakes
Using AzCopy for hundreds of terabytes over a slow link.
Offline database migration for a 24 by 7 system.
Skipping assessment. Compatibility blockers surface late.
Forgetting delta sync after Data Box.
Check yourself
Which service does offline bulk transfer to Azure?
The Azure Data Box family.
Which DMS mode gives minimal downtime?
Online.
Which tool replicates servers to Azure and cuts over?
Azure Migrate Server Migration.
Topic 7 of 10 in Design infrastructure solutions
Test yourself on Design infrastructure solutions
The full Microsoft AZ-305 question bank has 755 questions, with timed practice exams and an explanation for every answer.
This study guide is independent and is not affiliated with, endorsed by, or sponsored by Microsoft. Vendor names, certification names and exam codes are trademarks of their respective owners and are used for identification only.