What is the difference between scalability and elasticity?

Question

I\'ve heard many people using both terms interchangeably. However, in my opinion there is difference between them:

SCALABILITY - ability of a softwa

Answer 1

Scalability is the ability of the system to accommodate larger loads just by adding resources either making hardware stronger (scale up) or adding additional nodes (scale out).

Elasticity is the ability to fit the resources needed to cope with loads dynamically usually in relation to scale out. So that when the load increases you scale by adding more resources and when demand wanes you shrink back and remove unneeded resources. Elasticity is mostly important in Cloud environments where you pay-per-use and don't want to pay for resources you do not currently need on the one hand, and want to meet rising demand when needed on the other hand.