Book Image

Learning Azure Cosmos DB

By : Shahid Shaikh
Book Image

Learning Azure Cosmos DB

By: Shahid Shaikh

Overview of this book

<p>Microsoft has introduced a new globally distributed database, called Azure Cosmos DB. It is a superset of Microsoft's existing NoSQL Document DB service. Azure Cosmos DB enables you to scale throughput and storage elastically and independently across any number of Azure's geographic regions.</p> <p>This book is a must-have for anyone who wants to get introduced to the world of Cosmos DB. This book will focus on building globally-distributed applications without the hassle of complex, multiple datacenter configurations. This book will shed light on how Cosmos DB offers multimodal NoSQL database capabilities in the cloud at a scale that is one product with different database engines, such as key-value, document, graph, and wide column store. We will cover detailed practical examples on how to create a CRUD application using Cosmos DB with a frontend framework of your choice. This book will empower developers to choose their favorite database engines to perform integration, along with other systems that utilize the most popular languages, such as Node.js. This book will take you through the tips and trick, of Cosmos DB deployment, management, and the security offered by Azure Cosmos DB in order to detect, prevent, and respond to database breaches.</p> <p>By the end of this book, you will not only be aware of the best capabilities of relational and non-relational databases, but you will also be able to build scalable, globally distributed,<br />and highly responsive applications.</p>
Table of Contents (14 chapters)
Title Page
Packt Upsell
Contributors
Preface
Index

Failover handling


In the event of an Azure data center outage, Cosmos DB automatically triggers failovers of all Cosmos DB databases with a presence in the affected region.

There are two types of failover handling supported:

  1. Automatic failover handling
  2. Manual failover handling

Let's look at each of them briefly.

Automatic failover

If any read region fails, then Cosmos DB automatically disconnects that read region from a write region and diverts all its traffic to the preferred region list provided by the user.

If the user has not provided any region list then the traffic will be diverted to the main write region for further processing.

Once the read region is online, traffic will be automatically diverted to that region. All of this happens without a single line of code change in your application.

If the write region fails, then using a consensus protocol, another read region would be promoted as the write region. You can also specify which read region should become the write region in case of failure...