VMware Workload Migration Strategy - A Phased Approach Using MGN and EVS
Learn how to choose between MGN (Application Migration Service) and EVS when migrating VMware workloads to AWS, how to plan a phased migration, and how to optimize after migration.
Three Approaches to VMware Migration
There are three main approaches to migrating VMware workloads to AWS. The first, lift and shift, uses Amazon EVS to move the VMware environment as-is to AWS. No application changes are required, but VMware licenses are still needed. The second, replatforming, uses AWS MGN (Application Migration Service) to convert VMware VMs into EC2 instances. This frees you from VMware licensing, but requires OS and middleware compatibility verification. The third, refactoring, containerizes applications to run on ECS or EKS. This is the most cloud-native approach, but involves the highest application modification effort.
Migration Assessment and Planning
Before migration, use AWS Migration Hub to collect an inventory of your existing environment and map dependencies between workloads. Migration Evaluator (formerly TSO Logic) can analyze current on-premises usage data to calculate the optimal AWS configuration and cost estimates. Based on the assessment results, determine whether each workload should be migrated using EVS, MGN, or refactoring. As a guideline, workloads with high dependency on VMware-specific features (vMotion, DRS, HA) are suited for EVS, standard Linux/Windows servers for MGN, and applications that can be decomposed into microservices for refactoring.
Practical EC2 Migration with MGN
AWS MGN installs an agent on the source server and creates a replica on AWS through continuous block-level replication. The source server continues running during replication, so there is no impact on business operations. A test launch verifies the replica's operation, and if everything checks out, a cutover is executed to switch to production. Downtime during cutover is limited to the final differential sync time (typically a few minutes to tens of minutes). MGN's agent can coexist with VMware Tools, so it can be installed directly on servers in vSphere environments. After migration, the workload runs as an EC2 instance, enabling you to leverage AWS-native features such as Auto Scaling and ALB integration. To broaden your knowledge of migration projects, specialized books on Amazon can be a useful resource.
Migration Cost Considerations
MGN itself is free to use; the only costs are for the staging area (EC2 + EBS) used for replication. EVS's primary cost driver is dedicated host (i4i.metal) pricing, with a minimum 3-host configuration costing over $15,000 per month. The choice of migration method significantly impacts costs, so carefully evaluate the trade-off between MGN-based EC2 migration (lower cost, application changes required) and EVS-based VMware environment relocation (higher cost, no changes required). Use Migration Evaluator to analyze your current environment's costs and estimate post-migration TCO before deciding on an approach.
Summary - Recommended Phased Migration Strategy
For VMware workload migration to AWS, a phased strategy that selects between EVS and MGN based on workload characteristics is more effective than a single approach. Start by migrating development and test environments to EC2 with MGN to build cloud operations expertise, then lift and shift production environments with EVS before gradually converting them to EC2. After migration, optimize instance sizes with Compute Optimizer and reduce costs with Savings Plans. A phased departure from VMware licensing delivers long-term operational cost savings.