This is the single most-tested RDS distinction, and the wording is designed to trip you. Nail the difference and you’ll catch every variation.
Availability vs read scaling
Multi-AZ keeps a synchronous standby in another Availability Zone and fails over automatically — it’s about staying available, not speed. Read Replicas are asynchronous copies you send read queries to — they’re about scaling reads. You can use both together, but they solve different problems.
Test yourself
Your database is highly available already, but analytics queries are slowing down the primary. What should you add?
- Another Multi-AZ standby
- One or more Read Replicas
- A larger backup window
- A second security group
👉 Click to reveal the answer & explanation
Correct answer: B. Read Replicas offload read/analytics traffic and scale reads. Multi-AZ (A) is only for failover and wouldn’t reduce query load; backups (C) and security groups (D) are unrelated to read performance.
Related topics
Amazon RDS · Amazon Aurora · Amazon ElastiCache
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