Strange Loop

Zero Downtime Migrations of Stateful Systems

The Billing Infrastructure at Netflix needs to be up 24/7 to support 125+ million global customers. Billing systems are the source of truth for a customer's billing state which changes as customers apply gift cards, update their Method of Payment or just charged every month. We want this experience to be seamless and accurate anytime, day or night, so our databases are constantly in action, with no possible downtime windows. As systems evolve, they inevitably need to change. How do you meet those needs for change without incurring downtime?

We have succeeded in 2 major migrations. In the prior one, we migrated billions of rows from Oracle in our data center to MySQL in the AWS Cloud. In the recent one, we rewrote our legacy invoice processing system and seamlessly transitioned from a MySQL solution to Cassandra. All these efforts involved different strategies that helped us achieve these with a flip of a switch and without anyone realizing that Netflix did a major overhaul of its Billing Infrastructure.

Sangeeta Handa

Sangeeta Handa


Sangeeta Handa leads Billing Infrastructure Engineering at Netflix. She is as much passionate about building scalable and resilient software as she is about leading highly engaged and impactful engineering teams. At Netflix, she has led many successful efforts including Netflix Billing Infrastructure migration from native data center to AWS , rewrite of multiple important services related to invoicing customers, gift card and promotions tracking for customers. Prior to Netflix, Sangeeta evangelized and led construction of Apple's highly scalable financial reconciliation platform for mega million transactions in credit card payments, iPhone & gift card transactions. Other than these, she has also engineered many other systems, grounds up, that are still standing the test of time at Apple.