Minimizing churn in distributed systems

A pervasive requirement of distributed systems is to deal with churn — change in the set of participating nodes due to joins, graceful leaves, and failures. A high churn rate can increase costs or decrease service quality. This paper studies how to reduce churn by selecting which subset of a set of available nodes to use. First, we provide a comparison of the performance of a range of different node selection strategies in five real-world traces. Among our findings is that the simple strategy of picking a uniform-random replacement whenever a node fails performs surprisingly well. We explain its performance through analysis in a stochastic model. Second, we show that a class of strategies, which we call “Preference List” strategies, arise commonly as a result of optimizing for a metric other than churn, and produce high churn relative to more randomized strategies under realistic node failure patterns. Using this insight, we demonstrate and explain differences in performance f...

• Type: Conference
• Year: 2006
• Where: SIGCOMM
• Authors: Brighten Godfrey, Scott Shenker, Ion Stoica
• Keywords: Distributed Systems, Node Selection, Node Selection Strategies, SIGCOMM 2006