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Multi-region AWS migration

Zero-downtime cutover to a multi-region setup — 30% cost reduction, 99.99% uptime.

30%
Cost reduction
4 min
Cutover window
99.99%
Uptime SLA
<60s
Tested RTO
Multi-region AWS migration
A Norwegian SaaS company needed to migrate their monolithic deployment to a resilient multi-region AWS architecture without impacting 40,000+ daily active users. Cryton designed and executed the migration with a 4-minute read-only window — no alerts, no SLA breaches.
The Challenge

The client ran a single-region EU deployment with no failover, creating unacceptable risk for a platform with contractual uptime SLAs. Any outage window would erode client trust and trigger financial penalties. Infrastructure was provisioned by hand, with no IaC and no rollback capability.

Our Approach

We designed a multi-region active-passive architecture across us-east-1 and eu-west-1, with Route 53 latency-based routing and automated DNS failover. All infrastructure was codified in Terraform — replacing 100% of manual provisioning. RDS Aurora Global Database provided sub-second replica lag. A phased cutover runbook with automated rollback gates ensured zero risk on go-live day.

The Outcome

The live cutover completed in a single 4-minute maintenance window. Infrastructure costs fell 30% through Reserved Instances and right-sized compute. The client now has a fully automated DR procedure with a tested RTO under 60 seconds.

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