Consistent Hashing is a concept extensively used in Load Balancing. 

In a typical Load Balancer we use hashing in order to map the requests to their corresponding Servers.

 Here when we had to add or remove any Server then the Hash Values of all the earlier requests got modified which caused our cache to become obsolete

https://www.linkedin.com/pulse/consistent-hashing-even-load-distribution-skewed-problem-prateek/