Azure Cosmos DB for MongoDB

The Azure Cosmos DB API for MongoDB combines the power of MongoDB with the benefits of Azure Cosmos DB. MongoDB developers can use Azure Cosmos DB as if it were a MongoDB database while also gaining access to it. This is a fully managed, multi-model, NoSQL database as a service; reducing hassle from provisioning and resource management. There is an ability to scale up and down in real-time; no 24-hour wait to scale resources down to size. There is a flexible billing option to right-size cost to workload; access to a serverless consumption-based billing.

Features:

Guaranteed availability at any scale:

• Gain unparalleled speed and throughput, fast global access, and instant elasticity.
• Financially-backed SLAs for 99.999% high availability 
• Turn-key replication to any Azure region
• Multi-region writes for low latency
• Throughput options for different workloads

Mission-critical ready:

• Guarantee business continuity, 99.999% availability, and enterprise-level security for every application.
• Industry-leading 99.999% availability worldwide
• Distribute data globally with automatic data replication
• Zero downtime with multi-region writes or RPO 0 when using strong consistency.
• Enterprise-grade encryption-at-rest and self-managed keys

Fully managed and cost-effective:

• Managed database, with serverless deployments and cost-efficient instantaneous autoscale as well as a free tier to start at no cost.
• Handles maintenance and updates
• API upgrades were done with a single click and zero downtime
• Serverless and autoscale options 
• Free-tier discount: Get the first 1000 RU/s & 25 GB storage free monthly for one Azure Cosmos DB account per Azure subscription (free for the lifetime of the account)

Simplified app development:

• Leverage MongoDB drivers, no or minimal change to Application code, schema-less data, and no-ETL analytics over operational data.
• Leverage existing MongoDB drivers, libraries, and tools
• Built-in MongoDB shell
• ACID-compliant multi-document transaction support with API v4.2
• Deep integration with key Azure services including Azure Synapse Analytics 
• Change stream: Track and manage changes to database containers
• Emulator for local development

Migration with Azure:

1. Make data modernization easy with seamless migration of NoSQL workloads to the cloud
2. Bring app data from existing MongoDB deployments
3. Leverage existing tools, drivers, and libraries, and continue using existing apps’ current SDKs
4. Turnkey geo-replication
5. No infrastructure or VM management required
6. Automatic backups
7. Automatic API upgrades without interruption to data availability
   

Common Migration Methods:

Database Migration Service (Online and Offline mode both):

• Fully managed
• Simplifies, guides, and automates migration

Native MongoDB Tools (Offline):

• Familiar, easy to set up, and integrate
• mongodump & mongorestore – BSON-based
• mongoexport & mongoimport – JSON or CSV-based, Can be used to migrate a subset of data

Azure Data Factory (Offline):

• A fully managed, serverless data integration service