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What is auto-scaling? Horizontal vs vertical scaling.
FresherFundamentalsCloud Basics
Auto scaling
For What is auto-scaling? Horizontal vs vertical scaling., interviewers listen for a crisp definition, how the pieces interact in a real system, and one trade-off or failure mode you have seen or would guard against.
| Horizontal | Vertical | |
|---|---|---|
| Action | Add/remove instances | Bigger instance type |
| Pros | No downtime scale out | Simpler for small apps |
| Cloud | ASG + LB | Change instance class |
Scale on CPU/latency/custom CloudWatch metrics—not gut feel.