Originally sourced from searchaws.techtarget.com (December 2019). Guidance updated for editorial clarity.
Why VMware Cloud on AWS Migrations Require Careful Planning
VMware Cloud on AWS is a jointly developed hybrid cloud service sold and operated by VMware. It allows enterprises to extend their on-premises VMware environments into Amazon’s public cloud without requiring a full re-architecture of existing workloads. While that flexibility is genuinely attractive, the migration path from an on-premises data center to VMware Cloud on AWS introduces a set of challenges that teams frequently underestimate. Cost management, network reconfiguration, workload hygiene, and migration model selection all demand deliberate attention before a single VM is moved.
This article walks through the most common migration challenges and practical steps to address each one.
Challenge 1: Managing Migration Costs
Cost savings from a cloud migration rarely materialize immediately. During the transition, organizations typically run dual environments — the existing on-premises infrastructure alongside the new VMware Cloud on AWS deployment — which means paying for both simultaneously. Staff time, tooling, and potential downtime windows add further expense.
To keep costs under control:
- Perform traditional maintenance before migration begins. Clean up servers, apply outstanding OS and application patches, and decommission unused workloads before touching the migration toolchain.
- Rightsize CPU and memory resources. VMware Cloud on AWS can scale to meet almost any demand, but your budget cannot. Audit current resource allocation against actual utilization and resize accordingly prior to migration.
- Use a workload checklist. Physically track each server through the optimization process. A checked-off checklist prevents workloads from being moved in a degraded or bloated state.
Understanding that upfront investment is unavoidable — and budgeting for it — puts organizations in a much stronger position than discovering those costs mid-migration.
Challenge 2: Addressing Network Configuration Early
Network configuration is typically the first major obstacle in any AWS migration, and VMware Cloud on AWS is no exception. Regardless of how deeply embedded a workload is in its existing architecture, IT teams need a clear network migration strategy before VMs begin to move.
VMware Hybrid Cloud Extension (HCX)
VMware Hybrid Cloud Extension (HCX) is a network migration toolset bundled with VMware Cloud that significantly simplifies this process. Key HCX capabilities include:
- WAN optimization, compression, and deduplication — reduces the data volume transferred over the wire during migration.
- Layer 2 network stretching — allows VMs to be relocated without changing their IP addresses, a significant operational relief for application teams that rely on hard-coded addresses or complex DNS dependencies.
- Bulk and scheduled migration modes — supports both live vMotion and cold migration workflows.
One frequently cited advantage of HCX is that it can sustain migration throughput beyond the standard 250 Mbps vMotion bandwidth limit, making it more practical for organizations with constrained WAN links. HCX does require additional configuration steps to set up the network overlay between environments, but the Layer 2 stretching capability and WAN optimization generally justify that overhead.
It is worth noting that HCX cannot compensate for poor storage hygiene on the source VMs — a point covered in the workload optimization section below.
Challenge 3: Choosing the Right Migration Model
Once the network framework is in place, teams must decide between two broad migration strategies: a rebuild in the cloud or a lift-and-shift (forklift) migration.
Rebuild in the Cloud
A rebuild approach involves replicating workloads natively in VMware Cloud on AWS while keeping the on-premises systems running in parallel. Benefits include:
- A smaller cloud footprint optimized for the new environment
- Removal of legacy cruft — outdated software, stale configurations, unnecessary services
- A fresh start that can result in a more stable and better-performing platform
The tradeoff is time and labor. Rebuilding each workload is resource-intensive. For large or complex environments, the effort and cost may make this approach impractical.
Lift-and-Shift Migration
A lift-and-shift migration moves VMs to VMware Cloud on AWS largely as-is, either via live vMotion (minimal downtime) or a cold migration (brief planned outage). This is faster and less expensive in the short term, but it carries a critical risk: moving workloads without pre-migration cleanup means you are replicating existing problems into a paid cloud environment.
Common issues that inflate cloud storage costs during a lift-and-shift migration:
- Temporary files and patch remnants left on system drives
- Installation ISO files stored on server desktops or in downloads folders
- Runaway log files and abandoned application data
- Bloated profiles consuming disproportionate storage
Left unaddressed, these issues can easily double a server’s effective storage footprint when it moves to the cloud. HCX’s WAN optimization will not fix bad storage habits at the source — it simply transfers whatever is on the disk more efficiently.
Recommendation: Regardless of which model you choose, treat pre-migration workload cleanup as a non-negotiable step. Use the optimization checklist described in the cost management section above and sign off on each server before it enters the migration queue.
Challenge 4: Preventing Long-Term Waste Post-Migration
Moving to VMware Cloud on AWS does not automatically resolve existing configuration debt. Oversized VMs, misconfigured resources, and excess files all persist in the new environment — and in a consumption-based cloud model, those inefficiencies translate directly into ongoing monthly costs.
Steps to prevent waste from becoming a recurring problem:
- Establish a FinOps or cloud cost governance practice before or immediately after migration. Set budgets, tag resources consistently, and review utilization reports on a regular cadence.
- Implement automated rightsizing reviews. VMware Cloud on AWS exposes resource utilization data that can be used to identify over-provisioned VMs and reclaim capacity.
- Enforce storage hygiene policies. Define and communicate what is and is not acceptable to store on VM system drives. Automated policy enforcement tools can help maintain standards post-migration.
- Document misconfigurations found during migration. Use them as the basis for updated configuration standards going forward.
Summary: Key Actions Before You Migrate
| Migration Phase | Key Action |
|---|---|
| Pre-migration | Audit and rightsize CPU, memory, and storage on all workloads |
| Pre-migration | Apply OS and application patches; decommission unused VMs |
| Pre-migration | Clean up system drives, temp files, ISO files, and download folders |
| Network setup | Evaluate VMware HCX for Layer 2 stretching and WAN optimization |
| Migration planning | Choose rebuild vs. lift-and-shift based on timeline, budget, and complexity |
| Post-migration | Implement cloud cost governance and automated rightsizing reviews |
A VMware Cloud on AWS migration is not a shortcut to a clean, optimized cloud environment — it is a structured engineering project. Organizations that invest in pre-migration preparation consistently encounter fewer surprises, lower unexpected costs, and a more stable post-migration platform.