@Prince Rathod Welcome to Microsoft Platform. Thank you for posting your query here.
Scalable environments only care about increasing capacity to accommodate an increasing workload.
Elastic environments care about being able to meet current demands without under/over provisioning, in an autonomic fashion.
The key difference is, scalable systems don't necessarily mean they will scale up/down - it's only about being able to reach peak loads. Elastic workloads, however, will recognize dynamic demands and adapt to them, even if that means reducing capacity.
An example being, you have a web app that needs to support 1,000 active users for one day, so you meet that demand by provisioning 10 servers in total - but after that one day, you only ever have 10 active users, thus you only need 1 server. In this case, a scalable system would be able to scale to meet the 1,000 active users with the additional 9 servers - so that's cool, our system scaled! But now we're left with an abundance of over-provisioned capacity and we have to deal with that.
If our system was elastic for the above example, the process would have been automatic - our environment would have recognized the increasing workload, so it would have provisioned the necessary resources. Then when that day was over and the workload decreased significantly, our systems would have de-provisioned the servers as we didn't need them anymore.
Hope this helps!
Kindly let us know if the above helps or you need further assistance on this issue.
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