Infrastructure, security, and IT leaders · 8 min read

How to evaluate a cloud migration vendor

Cloud migrations go wrong in the places proposals skim over: network architecture, licensing that doesn't transfer, and ongoing costs — egress and compute — that aren't in the implementation quote at all. This guide covers what to interrogate before you sign a cloud migration (AWS, Azure, or Google Cloud).

Network design is frequently under-scoped

VPCs, subnets, transit gateways, firewall rules, and peering are routinely underscoped in migration proposals — and network design errors cause security incidents and performance failures at go-live. Require a network architecture deliverable, not an assumption.

Licence repatriation can add 20–40% to TCO

On-premises licences (Windows Server, SQL Server, Oracle DB) cannot always be used in the cloud. Licence repatriation analysis must be completed before the architecture is finalised — cloud licensing can add 20–40% to total cost of ownership if it's discovered late.

Egress and compute are ongoing costs the quote ignores

Cloud egress (data transferred out) and compute costs are significant, poorly understood, and excluded from implementation proposals. High-egress workloads can make cloud more expensive than on-premises. Model these against real workload patterns before committing.

Performance must be tested in the target environment

Application performance in the cloud depends on network latency, data-transfer costs, and resource sizing that can only be validated through load testing in the target environment. Most migration proposals exclude performance testing — put it back in scope.

Establish the security baseline first

Identity and access management, secrets management, encryption, logging, and threat detection must be established before workloads migrate, not after. A migration onto an unhardened landing zone is a breach waiting to happen.

Frequently asked

What is the most common cloud migration mistake?

Under-scoping the network architecture and ignoring ongoing egress and compute costs. Network design errors cause security and performance failures at go-live, and egress costs — excluded from the implementation quote — can make cloud more expensive than on-premises for high-transfer workloads.

Why does cloud cost more than expected?

Because the implementation quote omits the ongoing costs: egress (data transferred out), compute at production scale, and licence repatriation, which alone can add 20–40% to TCO. Model these against real workload patterns before signing.

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