What was the largest volume of data stored?

In one of the projects where I worked as a senior Java developer, the largest volume of stored data was about several terabytes. It was a system for processing and analyzing big data, where billions of records were received daily.

Distributed databases and storage systems such as Apache Hadoop and Cassandra were used for storage. The application employed data optimization methods: lazy loading, caching, table partitioning, and asynchronous processing.

Such volume required special attention to scalability, fault tolerance, and system performance.