Designing distributed systems using approximate synchrony in data center networks
Dan R. K. Ports, Jialin Li, Vincent B. Liu, Naveen Sharma, Arvind Krishnamurthy · 2015
Distributed systems are traditionally designed indepen-dently from the underlying network, making worst-case assumptions (e.g., complete asynchrony) about its behav-ior. However, many of today’s distributed applications are deployed in data centers, where the network is more re-liable, predictable, and extensible. In these environments, it is possible to co-design distributed systems with their network layer, and doing so can offer substantial benefits. This paper explores network-level mechanisms for pro-viding Mostly-Ordered Multicast (MOM): a best-effort ordering property for concurrent multicast operations. Us-ing this primitive, we design Speculative Paxos, a state machine replication protocol that relies on the network to order requests in the normal case. This approach leads to substantial performance benefits: under realistic data cen-ter conditions, Speculative Paxos can provide 40 % lower latency and 2.6 × higher throughput than the standard Paxos protocol. It offers lower latency than a latency-optimized protocol (Fast Paxos) with the same throughput as a throughput-optimized protocol (batching). 1