Microsoft Certified: Azure Solutions Architect ExpertDesign infrastructure solutionsHard

A global e-commerce company is designing a new platform that requires a highly available and globally distributed database. The database must support multiple write regions, automatic failover, and provide single-digit millisecond latency for reads and writes anywhere in the world. The data model is predominantly document-based. Which Azure database service is BEST suited for these requirements?

  1. AAzure Cosmos DB
  2. BAzure SQL Database
  3. CAzure Database for PostgreSQL
  4. DAzure Cache for Redis
Show answer & explanation

Correct answer: A. Azure Cosmos DB

Azure Cosmos DB is a globally distributed, multi-model database service that offers turn-key global distribution with multiple write regions, automatic failover, and guaranteed single-digit millisecond latency at the 99th percentile anywhere in the world. Its document model support aligns well with the stated data model.

Why the other options are wrong

  • B. Azure SQL Database is a relational database and while highly available, it does not offer multi-write region global distribution with single-digit millisecond latency guarantees globally.
  • C. Azure Database for PostgreSQL is a relational database and lacks the native multi-write region global distribution and guaranteed low latency of Cosmos DB.
  • D. Azure Cache for Redis is an in-memory data store for caching, not a primary globally distributed database.

Azure Cosmos DB

A globally distributed, multi-model database service that offers turn-key global distribution, elastic scaling of throughput and storage, and guaranteed low latency.

  • Globally distributed with multi-write regions
  • Guaranteed single-digit millisecond latency
  • Supports various NoSQL APIs (document, key-value, graph, column-family)

Memory trick: Cosmos DB: A universe of data, everywhere, fast.

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