Azure Databases Architecture Hub 🗄️⚡
Microsoft Azure provides a comprehensive database ecosystem spanning fully managed relational database management systems (RDBMS), globally distributed multi-model NoSQL, hyperscale storage engines, and enterprise in-memory caches.
Architectural Decision Matrix
Database Workload
│
┌─────────────────────────────┼─────────────────────────────┐
▼ ▼ ▼
Relational (OLTP / SQL) Distributed NoSQL / Global In-Memory Caching
│ │ │
┌───────┴───────┐ [[Azure/databases/cosmos-db|Azure Cosmos DB]] [[Azure/databases/redis/README|Azure Cache for Redis]]
▼ ▼ - Multi-Region Multi-Master - Sub-ms Key-Value
Proprietary Open Source - 5 Consistency Levels - Enterprise Clustering
│ │ - NoSQL, Mongo, Cassandra - Active-Active CRDT
▼ ▼
[[Azure/databases/azure-sql|Azure SQL / MI]] ┌───────┴───────┐
- Hyperscale ▼ ▼
- Serverless [[Azure/databases/postgres-flexible/README|PostgreSQL Flex]] [[Azure/databases/mysql-flexible|MySQL Flex]]
- T-SQL - PgBouncer - Zone-Redundant
- Citus Scale - Autoscale IOPS
Database Capabilities Matrix
| Service | Engine & Paradigm | Scalability Model | Consistency & High Availability | Primary Use Case |
|---|---|---|---|---|
| Azure SQL Database & Managed Instance | Microsoft SQL Server (T-SQL) | Vertical vCore + Hyperscale (100 TB distributed storage) | 99.995% SLA, Auto-Failover Groups, Serverless auto-pause | Enterprise business logic, legacy SQL Server migration, complex stored procedures. |
| Azure Cosmos DB | Multi-Model NoSQL (Document, Key-Value, Graph) | Horizontal sharding across partition keys, Autoscale RUs | Active-active multi-region writes, 5 mathematical consistency levels | Global web apps, IoT telemetry, real-time personalization, gaming leaderboards. |
| PostgreSQL Flexible Server | Native PostgreSQL 14–16 | Up to 64 vCPUs / 32 TiB, built-in PgBouncer | Zone-redundant standby with automated failover (< 60–120s) | Modern cloud-native microservices, JSONB document querying, geospatial (PostGIS). |
| MySQL Flexible Server | Community MySQL 8.0 | Up to 64 vCPUs / 32 TiB, storage autogrow | Zone-redundant synchronous log replication | Open-source web platforms, e-commerce stores, LAMP/LEMP application stacks. |
| Azure Cache for Redis | Redis 6.x/7.x & Redis Enterprise | Sharded clustering up to 2 TB RAM | In-memory replication, AOF/RDB persistence, active-active multi-region | Session stores, sub-millisecond query caching, distributed locking, pub/sub queues. |
Service Catalog
- Azure SQL Database & Managed Instance — Single Database vs Elastic Pools vs Managed Instance, vCore vs DTU models, Serverless auto-pause, Hyperscale multi-tier architecture, and Auto-Failover Groups.
- Azure Cosmos DB — Request Units (RUs), 5 well-defined consistency levels (Strong, Bounded Staleness, Session, Consistent Prefix, Eventual), partition key design, and multi-region active-active writes.
- Azure Database for PostgreSQL Flexible Server — Zone-redundant HA failover, integrated PgBouncer connection pooling, storage autogrow, and customized maintenance windows.
- Azure Database for MySQL Flexible Server Architecture — Zone-redundant high availability, pre-provisioned vs Autoscale IOPS, read replicas, and server parameter tuning.
- Azure Cache for Redis Architecture & Enterprise Tiers — Basic vs Standard vs Premium (clustering, persistence) vs Enterprise (Redis modules, Active-Active geo-replication using CRDTs).
Multi-Cloud Equivalents
| Capability | Microsoft Azure | Amazon Web Services (AWS) | Google Cloud Platform (GCP) |
|---|---|---|---|
| Enterprise Relational | Azure SQL Database | Amazon Aurora / RDS SQL Server | Cloud SQL / AlloyDB |
| Managed PostgreSQL | PostgreSQL Flexible Server | Amazon RDS for PostgreSQL / Aurora | Cloud SQL for PostgreSQL / AlloyDB |
| Managed MySQL | MySQL Flexible Server | Amazon RDS for MySQL / Aurora | Cloud SQL for MySQL |
| Globally Distributed NoSQL | Azure Cosmos DB | Amazon DynamoDB | Cloud Spanner / Cloud Bigtable |
| Managed Redis Cache | Azure Cache for Redis | Amazon ElastiCache / MemoryDB | Memorystore for Redis |