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Zero-Outage Cloud Migration Across 400 Workloads
Two acquisitions had left a global carrier operating four data centers across three virtualization stacks. The DORIAN Group mapped the estate, built an owned landing zone, and moved production workloads in nine waves without a single unplanned outage.
Client
Top-20 Global Carrier
Services
Cloud Migration
On This Page
The Challenge
Our Approach
The Outcome
The Challenge
Two acquisitions had expanded the carrier's infrastructure across four data centers and three virtualization stacks. The largest data-center lease expired in eighteen months, but claims processing could not go dark while production workloads moved.
The constraint was not simply technical migration. The work had to reduce dependency risk, sequence cutovers around live operations, and leave the carrier's platform team able to run the environment after the move.
Our Approach
Map Risk Before Moving Workloads
The DORIAN Group began with six weeks of discovery. The team mapped application dependencies and scored each workload for risk and effort, creating a migration sequence that allowed the organization to learn on lower-stakes systems before moving critical workloads.
Build For Client Ownership
The team built a cloud landing zone with accounts, networking, and guardrails designed for the carrier's engineers to own. This established a consistent operating foundation before the migration waves began.
Run Controlled Cutovers
Nine waves combined weekend cutovers with on-call support alongside the carrier's engineers. The delivery model kept the migration moving while preserving a direct path to decisions and recovery when a workload required additional attention.
Discover
Mapped dependencies across the estate and scored every application for risk and effort over six weeks.
Build
Created a landing zone with accounts, networking, and guardrails the carrier's team could operate.
Run
Completed nine migration waves with weekend cutovers and on-call support alongside client engineers.
The Outcome
The final data center closed one month ahead of lease expiry. Mean time to recovery dropped 60% against the pre-migration baseline, and the carrier's platform team now runs the environment without external support.
They did not hand us a plan and leave. Their engineers sat in our stand-ups until the last wave landed.
VP, Infrastructure