Inside a Real-World Cloud Migration: What We Learned Moving 40+ Servers to AWS
Inside a Real-World Cloud Migration: What We Learned Moving 40+ Servers to AWS
Peek behind the curtain: lessons, pitfalls, and quick wins from our multi-phase AWS migration for a major international organization. We share honest numbers, gotchas, and how strong client collaboration kept the project on track.
Why This Project Mattered
In 2024–2025, Forteneer was selected to lead the migration and modernization of the IT backbone for a large multi-site organization operating in the Americas—responsible for mission-critical workloads supporting thousands of daily users. The environment included over 40 critical production servers and a dozen development/test systems, running everything from ERP and learning platforms to legacy Windows servers and custom databases.
This wasn’t a “lift and shift.” The client needed better uptime, cost control, disaster recovery, and a platform for future AI/analytics. And it had to be done with minimal disruption, tight budgets, and rapid upskilling of their in-house IT team.
Key Lessons and “Aha” Moments
1. “Discovery is Never as Simple as It Sounds”
Everyone wants to skip to the fun part—spinning up EC2s. But our team spent weeks mapping the real environment:
- 40+ servers, multiple OS versions, complex domains
- Mix of ERP, web, email, student info, and custom apps
- Unknown firewall rules and overlapping private IPs
Takeaway: If you don’t document and challenge every assumption, you’ll hit a wall by Week 2.
2. Network, Identity, and Security Can’t Wait Until Go-Live
We ran into old Active Directory domains, hardcoded IP dependencies, and inconsistent firewall rules (mix of Fortinet, Zyxel, and legacy gear). Getting the AWS VPC design right—CIDR planning, subnets, VPN, NAT, firewalls—was crucial to avoid massive downtime later.
Takeaway: A migration is always a networking project in disguise.
3. Cost Surprises—For Better and Worse
We modeled every option: on-demand, reserved, and savings plans. Real cost came in 30–50% lower than the client’s estimates for on-prem hardware refresh, but we did have to manage a few “bill spikes” from leftover test instances and improper S3 lifecycles. Partnering with AWS and our global distribution network helped us secure credits and temporary boosts for migration phases.
Takeaway: Cloud saves money—if you actually track what’s running and shut down what you don’t need.
4. Migration Success = 70% Change Management, 30% Tech
No migration plan survives contact with reality. Apps with hardcoded file paths, surprise legacy dependencies, or mystery service accounts will throw wrenches at you. What worked:
- Constant multi-channel check-ins
- Live documentation of every change
- Immediate rollback plans for each cutover
Takeaway: Strong collaboration and over-communication are the only way through.
Our Quick Wins
- Reduced planned downtime by 60% vs. traditional migration approaches
- Helped the client IT staff master AWS tools within 2 months
- Delivered working disaster recovery playbooks, not just documentation
- Enabled future AI/data projects by modernizing data access
Looking Forward
This project proved that even organizations with complex, legacy environments can move to AWS—successfully and affordably—if you combine real discovery, honest cost modeling, and real-time collaboration. No magic, just relentless execution.
Ready to talk about your own migration? We’ve got the scars, and we’re not afraid to share.
