In a feat of technological choreography, Uber successfully transitioned petabytes of financial transaction data to a brand new in-house database, LedgerStore, without causing any downtime to its core services. This migration involved moving a staggering trillion individual records, highlighting Uber's commitment to robust data infrastructure and cost optimization.
Previously, Uber relied on DynamoDB, a cloud-based NoSQL database for storing its financial data. However, as the volume of transactions grew exponentially, so did the associated storage costs. To address this challenge, Uber implemented a tiered storage system, keeping only the most recent data (roughly 12 weeks' worth) in DynamoDB and archiving older data in TerraBlob, an internal service similar to Amazon's S3 object storage.
The long-term solution, however, came in the form of LedgerStore. Unlike DynamoDB, LedgerStore is a custom-built database specifically designed for financial data. This bespoke approach offers several advantages. LedgerStore leverages a ledger-style architecture, ensuring data immutability through cryptographic signatures. This immutability is crucial for financial transactions, as it guarantees that past records cannot be tampered with. Additionally, LedgerStore is optimized for the specific needs of financial data, offering improved performance and scalability compared to generic NoSQL solutions.
Migrating such a massive dataset while maintaining service continuity was no easy feat. Uber engineers meticulously planned and executed a multi-phased approach. A key aspect involved configuring LedgerStore to operate alongside DynamoDB. During this phase, data was continuously replicated between the two systems, ensuring consistency and enabling a seamless switchover. Once the data replication was complete, Uber strategically redirected online traffic to query LedgerStore as the primary source. This redirection process itself was meticulously divided into four stages, allowing for rollback or forward progress as needed.
The successful migration to LedgerStore brings Uber several benefits. Firstly, the custom-built architecture offers significant cost savings compared to relying solely on cloud-based solutions like DynamoDB. Secondly, LedgerStore's ledger-style design bolsters data security and integrity. Finally, the new database is optimized for handling financial transactions, ensuring efficient performance and scalability as Uber's business continues to expand.
This migration serves as a testament to Uber's commitment to innovation and efficient data management. By developing a bespoke solution tailored to its specific needs, Uber has achieved significant cost savings, enhanced data security, and ensured a robust foundation for future growth.