====== Multi-AZ ======

**What it is:** Deploying across multiple Availability Zones.

**What it’s for:**
  * Survive an AZ failure with minimal downtime.
  * Enable *failover* /ˈfeɪlˌoʊvər/ (chuyển dự phòng).

**How it’s used (examples):**
  * **RDS Multi-AZ**: primary in one AZ, standby in another AZ; automatic failover.
  * **Load balancer + EC2**: instances in 2+ AZs behind an ALB/NLB.

**Exam cues:**
  * “same endpoint, automatic failover” → often points to RDS Multi-AZ.
  * “strict HA requirement” → Multi-AZ design.

**Hard words:**
  * *failover* /ˈfeɪlˌoʊvər/: chuyển dự phòng
  * *standby* /ˈstændbaɪ/: chờ sẵn
  * *downtime* /ˈdaʊntaɪm/: thời gian gián đoạn