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Updated 15 Jul 2026 • 8 mins read

Successful AWS migrations map tools to phases: Application Discovery Service for assessment, Migration Hub for orchestration, Application Migration Service for lift-and-shift servers, Database Migration Service for schemas and data, and DataSync for file and object transfer. This guide covers each tool, the 7 Rs framework, and the cost discipline migrations deserve from day one.
Every AWS migration is really three projects wearing one name: understanding what you have, moving it safely, and not regretting the bill afterward, and AWS ships purpose-built tooling for the first two while most teams improvise the third. This guide covers the five tools that carry nearly every migration, mapped to the phase each serves, plus the framework that decides what gets migrated how, and the cost practices that separate migrations that land lean from the lift-and-shift projects that spend their first cloud year paying for their data center's old habits.
A framing note: the best migration tool is the one matched to the workload's migration strategy, so we start with the strategy vocabulary, the 7 Rs, and then meet the tools in the order a migration actually uses them.
Key takeaway Five tools cover the standard AWS migration path: AWS Application Discovery Service inventories on-premises servers, dependencies, and utilization to build the migration case; AWS Migration Hub is the control tower that tracks every workload across tools and waves; AWS Application Migration Service (MGN) is the primary lift-and-shift engine, continuously replicating servers for minimal-downtime cutover; AWS Database Migration Service (DMS) moves databases, with schema conversion for cross-engine moves and continuous replication for near-zero-downtime cutovers; and AWS DataSync moves file and object data at scale. The discipline that should ride along: tag every migrated resource on arrival, size instances from measured utilization rather than data center specs, and treat the migration itself as the single best rightsizing opportunity the estate will ever get.
AWS's migration framework sorts every workload into one of seven strategies: retire (decommission instead of migrating, the cheapest move in the portfolio), retain (leave on-premises for now), rehost (lift-and-shift, the volume play), relocate (move at the hypervisor or platform level where supported), replatform (lift-and-optimize, small changes like managed databases on the way over), repurchase (move to SaaS), and refactor (re-architect for cloud-native, the deepest and most expensive). The portfolio mix determines the tooling mix, rehost-heavy migrations lean on server replication, database moves lean on DMS, and every honest assessment finds retire candidates nobody wanted to admit, which is why the process starts with discovery rather than migration.
Migrations fail in inventory more than in transit: the undocumented dependency, the server nobody owned, the utilization assumption that was folklore. Application Discovery Service builds the factual baseline, via lightweight agents or agentless collection, capturing server inventories, specifications, measured utilization, and network dependencies, feeding both the wave planning (what moves together) and the business case (what it should cost to run). Two companions round out assessment: Migration Evaluator for the executive-grade cost projection, and the discovered utilization data itself, which becomes the rightsizing input later, a data center server at 12 percent CPU should not become a cloud instance sized for its label. Assessment is also where the TCO conversation gets honest numbers instead of vendor calculators.
A real migration runs dozens to thousands of workloads across multiple tools, waves, and teams, and Migration Hub is where that stays coherent: a single view of discovery data and migration status across the AWS migration tooling, progress tracked per application rather than per server, and wave orchestration so cutovers happen in dependency order. It is free, it is the natural home of the migration's operating rhythm (the weekly wave review), and its quiet value is organizational: one dashboard that finance, engineering, and leadership all read ends the status-by-spreadsheet era that migrations otherwise default to.
MGN is the workhorse for rehost strategies: a lightweight agent continuously replicates source servers, physical, virtual, or other-cloud, into a staging area block by block, keeping them in sync until cutover, when the workload launches on right-sized EC2 infrastructure with downtime measured in minutes rather than weekends. The continuous-replication model is what makes it safe: test launches run against real replicated data without touching the source, cutover windows shrink to a final sync, and rollback remains possible until you commit. Practical notes: replication during the migration window carries generous free-period terms (verify current specifics), and MGN's launch templates are where rightsizing decisions actually get enforced, the discovery data from tool one should set these, not the source server's nameplate.
Databases are the migration's highest-stakes cargo, and DMS is built for exactly that anxiety: continuous replication from source to target keeps the destination in sync while the source stays live, shrinking cutover downtime toward minutes, with support for homogeneous moves (like-for-like engines) and heterogeneous ones (cross-engine, paired with schema conversion tooling that translates schemas, and flags what needs human hands). Common patterns: on-premises databases into managed RDS or Aurora as a replatform move, ongoing replication for phased cutovers, and validation tooling to prove row-level fidelity before anyone flips traffic. Cost notes: DMS bills for the replication capacity you run, and the destination choice is the real financial decision, managed database services trade instance-level control for operational savings, and the database commitment options that arrived at re:Invent 2025 make reserved pricing on the destination part of the plan, once usage stabilizes.
Servers and databases move with the tools above; the terabytes of file shares, archives, and object data move with DataSync: an agent-based transfer service that moves data between on-premises storage (NFS, SMB, object stores) and AWS storage services over the network, with built-in scheduling, bandwidth throttling, integrity verification, and incremental sync. It bills per gigabyte transferred (verify current rates), and its planning question is bandwidth arithmetic: data volume over available network capacity gives the calendar, and where the math says months, AWS's offline transfer options (the Snow device family, where currently offered) exist for exactly that case. The quiet cost decision inside every DataSync plan is the destination storage class: landing archival data in hot storage and tiering it later is a common and entirely avoidable tax, set lifecycle policies before the data arrives.
| Tool | Migration phase | What it does | Cost note |
|---|---|---|---|
| Application Discovery Service | Assess | Inventory, utilization, dependency mapping | Free; its utilization data drives rightsizing |
| Migration Hub | Orchestrate | Single tracking view across tools and waves | Free; the migration's operating dashboard |
| Application Migration Service | Migrate servers | Continuous replication, minimal-downtime cutover | Free replication window (verify current terms); size launches from data |
| Database Migration Service | Migrate databases | Continuous replication, schema conversion, validation | Pay for replication capacity; destination choice is the real decision |
| DataSync | Migrate data | Scheduled, verified file and object transfer | Per-GB pricing; set destination storage class and lifecycle policies first |
The selection logic is phase-driven rather than competitive: every migration wants Discovery and Migration Hub (both free, both foundational), rehost waves add MGN, database moves add DMS, and bulk data adds DataSync, with third-party tooling (backup-vendor migrators, specialized database tools, migration consultancies' platforms) earning a place mainly for edge cases the native path handles awkwardly. The more consequential choices are the ones the tools implement rather than make: the 7 Rs mix, the destination architecture, and the cost management posture waiting on the other side, which is why the best migration plans read as one part logistics, one part optimization strategy.
Each tool offers unique strengths in the migration process. For instance, AWS Migration Hub can coordinate migrations executed through DMS or Fivetran, keeping all activities aligned and synchronised.
Choosing the right AWS migration tools is essential for a smooth, secure, and efficient move to the cloud. Each solution brings its own strengths—from automated lift-and-shift capabilities to real-time replication and intelligent monitoring. When combined, they create a powerful ecosystem that supports every stage of the migration journey, ensuring organisations achieve long-term performance, reliability, and scalability in the cloud.
Five cover the standard path: AWS Application Discovery Service (assessment and dependency mapping), AWS Migration Hub (orchestration and tracking), AWS Application Migration Service (lift-and-shift server replication), AWS Database Migration Service (database moves with schema conversion), and AWS DataSync (file and object data transfer).
The strategy vocabulary: retire, retain, rehost (lift-and-shift), relocate, replatform (lift-and-optimize), repurchase (move to SaaS), and refactor (re-architect). The portfolio mix across the seven determines which tools carry the migration and how much post-move optimization remains.
The primary rehost engine: an agent continuously replicates source servers, physical, virtual, or other-cloud, into AWS, supports non-disruptive test launches against replicated data, and cuts over with downtime measured in minutes, with launch templates enforcing the instance sizing you actually want.
Continuous replication keeps the target in sync while the source stays live, shrinking cutover downtime toward minutes, with schema conversion tooling for cross-engine moves and validation to prove data fidelity. You pay for the replication capacity you run during the migration.