Performance Comparison of a Rotating Coordinator and a Leader Based Consensus Algorithm

Performance Comparison of a Rotating Coordinator and a Leader Based Consensus Algorithm Peter Urban, Naohiro Hayashibara, Andre Schiper, and Takuya Katayama Protocols that solve agreement problems are essential building blocks for fault tolerant distributed systems. While many protocols have been published, little has been done to analyze their performance, especially the performance of their fault tolerance mechanisms. In this paper, we compare two well-known asynchronous consensus algorithms. In both algorithms, a leader process tries to impose a decision, and another leader retries if the leader fails doing so. The algorithms elect leaders differently: the Chandra-Toueg algorithm has a rotating leader, whereas processes in the Paxos algorithm elect leaders directly. We investigate the performance implications of this difference. In the system under study, processes send atomic broadcasts to each other. Consensus is used to decide the delivery order of messages. We evaluate the steady state latency in (1) runs with neither crashes nor suspicions, (2) runs with crashes and (3) runs with no crashes in which correct processes are wrongly suspected to have crashed, as well as the transient latency after (4) one crash and (5) multiple correlated crashes. The results show that the Paxos algorithm tolerates frequent wrong suspicions (3) and correlated crashes (5) better, while the performance is comparable in all other scenarios. Keywords: simulation, consensus, atomic broadcast, rotating coordinator, leader, asynchronous, failure detector

Comparison of Failure Detectors and Group Membership: Performance Study of Two Atomic Broadcast Algorithms

André Schiper

Peter Urban, Ilya Shnayderman and Andre Schiper Comparison of Failure Detectors and Group Membership: Performance Study of Two Atomic Broadcast Algorithms In Proc. of the 2003 International Conference on Dependable Systems and Networks (DSN), pages 645-654 Protocols that solve agreement problems are essential building blocks for fault tolerant distributed systems. While many protocols have been published, little has been done to analyze their performance, especially the performance of their fault tolerance mechanisms. In this paper, we present a performance evaluation methodology that can be generalized to analyze many kinds of fault-tolerant algorithms. We use the methodology to compare two atomic broadcast algorithms with different fault tolerance mechanisms: unreliable failure detectors and group membership. We evaluated the steady state latency in (1) runs with neither crashes nor suspicions, (2) runs with crashes and (3) runs with no crashes in which correct processes are wrongly suspected to have crashed, as well as (4) the transient latency after a crash. We found that the two algorithms have the same performance in Scenario 1, and that the group membership based algorithm has an advantage in terms of performance and resiliency in Scenario 2, whereas the failure detector based algorithm offers better performance in the other scenarios. We discuss the implications of our results to the design of fault tolerant distributed systems.

2003

Comparison of Failure Detectors and Group Membership: Performance Study of Two Atomic Broadcast Algorithms

André Schiper

Protocols that solve agreement problems are essential building blocks for fault tolerant distributed systems. While many protocols have been published, little has been done to analyze their performance, especially the performance of their fault tolerance mechanisms. In this paper, we present a performance evaluation methodology that can be generalized to analyze many kinds of fault-tolerant algorithms. We use the methodology to compare two atomic broadcast algorithms with different fault tolerance mechanisms: unreliable failure detectors and group membership. We evaluated the steady state latency in (1) runs with no crashes and no suspicions, (2) runs with crashes and (3) runs with no crashes in which correct processes are wrongly suspected to have crashed, as well as (4) the transient latency after a crash. We found that the two algorithms have the same performance in Scenario 1, and that the group membership based algorithm has an advantage in terms of performance and resiliency in Scenario 2, whereas the failure detector based algorithm offers better performance in the other scenarios. We discuss the implications of our results to the design of fault tolerant distributed systems.

2003

Comparison of Failure Detectors and Group Membership: Performance Study of Two Atomic Broadcast Algorithms (extended version)

André Schiper

Protocols that solve agreement problems are essential building blocks for fault tolerant distributed systems. While many protocols have been published, little has been done to analyze their performance, especially the performance of their fault tolerance mechanisms. In this paper, we present a performance evaluation methodology that can be generalized to analyze many kinds of fault-tolerant algorithms. We use the methodology to compare two atomic broadcast algorithms with different fault tolerance mechanisms: unreliable failure detectors and group membership. We evaluated the steady state latency in (1) runs with neither crashes nor suspicions, (2) runs with crashes and (3) runs with no crashes in which correct processes are wrongly suspected to have crashed, as well as (4) the transient latency after a crash. We found that the two algorithms have the same performance in Scenario 1, and that the group membership based algorithm has an advantage in terms of performance and resiliency in Scenario 2, whereas the failure detector based algorithm offers better performance in the other scenarios. We discuss the implications of our results to the design of fault tolerant distributed systems.

2003