Amazon.com, Inc.
Arc jump: per-key selection of an alternative server when implemented bounded loads

Abstract:

Systems and methods are described for implementing an "arc jump" technique in conjunction with bounded loads in consistent hashing. In general, bounded loads refers to limiting the ability of a single device within a distributed system to store data objects, such that when a request to store a new data object would otherwise be directed to that device, it is instead redirected to an alternative device. Redirecting all requests to a single alternative device can lead to cascading failures, as the alternative device must maintain its own load and that which has been redirected to it. Embodiments of the present disclosure address this by determining an alternative device on a per-object basis, such as by again hashing the object with an additional seed value. This distributes request from an overloaded device among all other devices of the distributed system, avoiding cascading failures.