Quick Answer
Vertical scaling: add more CPU/RAM to the existing machine. Simple, no code changes, works up to hardware limits, requires downtime. Horizontal scaling: add more machines/instances. No hardware limit (in cloud), high availability, but requires stateless services and load balancing. Cloud-native systems favor horizontal scaling - vertical scaling is used to right-size instances.
Answer
Vertical: Add CPU/RAM to existing instance (limited). Horizontal: Add more instances (preferred). Horizontal scaling supports elasticity and fault tolerance.
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SugharaIQ Editorial Team
Verified Answer
This answer has been peer-reviewed by industry experts holding senior engineering roles to ensure technical accuracy and relevance for modern interview standards.
