Checkpointing Models for Tasks with Widely Different Processing Times

Abstract

A server subject to random breakdowns and repairs offers services to incoming jobs whose lengths are highly variable. A checkpointing policy aiming to protect against possibly lengthy recovery periods is in operation. The problem of how to choose a checkpointing interval in order to optimize performance is addressed by analysing a general queueing model which includes breakdowns, repairs, back-ups and recoveries. Exact solutions are obtained under both Markovian and non-Markovian assumptions. Numerical experiments illustrate the conditions where checkpoints are useful and where they are not, and in the former case, quantify the achievable benefits.