eBay has implemented a robust multi-data center architecture using MongoDB, with over 3,000 non-relational database instances managing multiple petabytes of data. To ensure high availability and resilience, the company's DBA team has developed "Resiliency Design Patterns" that take into account factors such as consistency, durability, recoverability, scalability, performance, and application behavior. These patterns are used to power various applications, including the eBay product catalog, which uses a 50-member replica set for massive data distribution and read scalability. The company also has an "Extreme High Read / Write Pattern" that distributes a sharded MongoDB cluster across its US data centers. With recent enhancements to MongoDB, such as zone sharding and retryable writes, eBay is able to serve applications with distributed, always-on write availability and reduce application-side exception handling code.