DocumentDB is born in the cloud and backed by blazingly fast, low-latency, write-optimized, solid-state drive (SSD) storage. Achieve fast, predictable performance with reserved resources to deliver on your throughput needs. Storage and throughput scale linearly with cost via combinable units as application needs grow. Tune and trade off consistency through well-defined levels—strong, bounded-staleness, session, and eventual—to suit application scenarios and performance needs instead of facing the challenge of choosing between the two extremes of strong and eventual consistency. Data is automatically replicated to provide high availability.