You are the engineering manager leading a migration from a single-region user profile service to a distributed, multi-region architecture for a consumer subscription platform. The business needs lower latency and higher resilience before peak seasonal traffic, but profile data now updates from web, mobile, billing, messaging, and moderation systems that do not agree on ordering or retry behavior. You have 12 weeks to launch in two new regions while keeping downstream experiences like account settings, notifications, and entitlement checks consistent enough that users do not see stale plans, duplicate messages, or incorrect access. The challenge is compounded by an executive push for a hard launch date tied to a marketing campaign, a payments dependency that cannot change its API contract this quarter, and a recent incident that made legal and support highly sensitive to any customer-visible data mismatch.
| Detail | Value |
|---|---|
| Timeline | 12 weeks to production launch |
| Team | 6 backend engineers, 2 SREs, 1 QA engineer |
| Regions | 3 total regions after launch |
| Peak traffic | 18K profile writes/sec, 120K reads/sec |
| Data sources | 5 upstream systems writing profile-related state |
| Availability target | 99.95% |
| Customer impact tolerance | No more than 0.1% inconsistent reads during rollout |
| Compliance | GDPR deletion and auditability required |
How would you plan and execute this launch so that data consistency risks are understood, trade-offs are explicit, and the rollout can proceed safely under the deadline? Explain how you would sequence the work, align stakeholders, and decide what level of consistency is acceptable for launch.