What is "load shedding"

n. 1 The process by which an electric utility cuts power to some customers in response to a shortage of available electricity. 2 The postponement of payment of less important bills because of financial problems.

Load Shedding is a technique used in information systems, especially web services, to avoid overloading the system and making it unavailable of all users. The idea of Load Shedding is to rather flatly ignore some requests rather than crashing a system and making it fail to serve any request.

Considerations shaping the design of load shedding algorithms include:

• when one of several load balanced servers becomes unavailable due to overload, all other servers will receive a higher load, potentially leading to more overload and a snow-ball effect which takes down the entire system.
• when one part in a system of microservices starts becoming slower due to high load, other services will have waiting requests queuing up, potentially more than fits in their memory, which could again take down the entire system.

A popular open-source tool for defending against delays in downstream systems is Hystrix 1.