Azure Cosmos DB is a superset of the existing DocumentDB service, and Microsoft is transitioning all existing DocumentDB customers to Azure Cosmos DB, free of charge.
The system is designed to scale horizontally, whilst maintaining impressive performance and reliability. This is backed by a confident and generous service-level agreement.
Microsoft says that it can deliver single-digit millisecond latency at the 99th percentile, which is huge. It also says that 99.99 percent of all requests will “complete successfully,” and is also promising a 99.99 percent uptime availability.
This new effort from Redmond is extremely versatile, and can handle pretty much every type of data you’re likely to throw at it, including key-value, document, columnar, and graph types, in a variety of environments, including AI and IoT.
Azure Cosmos DB also plays nice with several NoSQL APIs including MongoDB, Table Storage, DocumentDB SQL, Gremlin, and Azure Tables. The Gremlin and Table Storage are currently in preview mode.
Another strength of Azure Cosmos DB is the ease and speed upon which data can be replicated in different Azure regions, allowing developers to quickly respond to regional surges of traffic. This elasticity doesn’t come at the expense of application downtime.