HDFS is a Java-based file system that provides scalable and reliable data storage, and it was designed to span large clusters of commodity servers. HDFS has demonstrated production scalability of up to 200 PB of storage and a single cluster of 4500 servers, supporting close to a billion files and blocks.
Google Cloud SQL for PostgreSQL is a fully-managed database service that makes it easy to set up, maintain, manage, and administer your relational PostgreSQL databases in the cloud.