Azure cloud migration follows a structured sequence of steps — discover, assess, plan, migrate, optimize — that reduces risk and ensures workloads perform well in their new environment. This guide walks through each step with specific Azure tools and timeline estimates.
Step 1: Discover Your Environment
Discovery creates a complete inventory of servers, databases, and applications that need to migrate. Azure Migrate provides two discovery options:
- Agentless discovery: Deploy the Azure Migrate appliance as a virtual machine on your VMware or Hyper-V host. It scans your environment without installing anything on target servers.
- Agent-based discovery: Install the Azure Migrate agent on each server for deeper dependency mapping and performance data collection
Run discovery for at least 30 days to capture representative performance data. This data drives accurate sizing recommendations in the assessment phase.
Step 2: Assess and Plan
Assessment produces right-sizing recommendations, cost estimates, and a migration readiness report for each workload. Key assessment activities:
- Run Azure Migrate assessment to generate VM sizing and cost estimates
- Map application dependencies using dependency analysis (agent-based or agentless)
- Classify workloads using the 6 Rs: Rehost, Replatform, Refactor, Repurchase, Retire, Retain
- Build a migration wave plan grouping related applications for coordinated cutover
| Strategy | Azure Tool | Effort | Best For |
|---|---|---|---|
| Rehost | Azure Migrate (Server Migration) | Low | VMs with minimal changes |
| Replatform | Azure App Service, Azure SQL | Medium | Apps benefiting from PaaS |
| Refactor | Azure Kubernetes Service, Functions | High | Apps needing cloud-native features |
| Repurchase | Microsoft 365, Dynamics | Medium | Replacing with SaaS |
Step 3: Prepare the Landing Zone
The landing zone is your Azure foundation — subscriptions, networking, identity, and security baselines that all migrated workloads will inherit.
- Deploy Azure Landing Zones using the Cloud Adoption Framework accelerator
- Configure hub-and-spoke networking with ExpressRoute or VPN connectivity
- Set up Microsoft Entra ID with conditional access and MFA
- Apply Azure Policies for governance, tagging, and compliance
- Configure Microsoft Defender for Cloud for security posture management
Step 4: Migrate Workloads
Execute migration in waves, starting with lower-risk workloads and building velocity with each successive wave. Primary migration tools:
- Azure Migrate (Server Migration): Continuous replication for VMware, Hyper-V, and physical servers with automated cutover
- Azure Database Migration Service: Online and offline migration for SQL Server, MySQL, PostgreSQL, and MongoDB
- Azure Storage Migration Service: File server migration with identity and permission mapping
- Azure Data Box: Offline data transfer for large datasets (up to 1 PB per order)
Each wave follows a standard pattern: replicate, test, cut over, validate, decommission source. For migration strategy details, see our strategy guide.
Step 5: Optimize and Govern
Post-migration optimization captures savings from right-sizing, reserved capacity, and architectural improvements.
- Review Azure Advisor recommendations for right-sizing and cost savings
- Implement Reserved Instances or Savings Plans for predictable workloads
- Set up Azure Cost Management budgets and alerts
- Schedule a Well-Architected Review to identify improvement opportunities
- Configure Azure Monitor for performance baselines and alerting
Migration Timeline Estimates
Realistic timelines depend on portfolio size and organizational readiness.
- Small (5-20 servers): 2-4 months including assessment and optimization
- Medium (20-100 servers): 4-8 months with 2-4 migration waves
- Large (100+ servers): 8-18 months with dedicated migration team
Frequently Asked Questions
Can I migrate from AWS to Azure?
Yes. Azure Migrate supports discovery and assessment of AWS EC2 instances. The server migration tool can replicate AWS VMs to Azure through agent-based replication.
What is the minimum downtime during migration?
For rehost migrations, downtime is typically 15-60 minutes per server during cutover. Azure Migrate uses continuous replication so only the final sync and IP switchover cause downtime.
How much does Azure migration cost?
Azure Migrate is free. You pay for Azure resources consumed after migration. Budget for 2-4 months of dual-running costs. Microsoft offers Azure Migrate and Modernize incentives for qualifying organizations.
Do I need to migrate all workloads at once?
No. Wave-based migration is recommended. Start with 5-10 low-risk servers in wave 1, learn from the experience, then increase wave size to 20-50 servers in subsequent waves.
What about application dependencies during migration?
Azure Migrate dependency analysis maps connections between servers and applications. Migrate dependent applications together in the same wave to avoid breaking interconnections during cutover.