Chathuri Lanchana Rubasinghe Gunawardhana


Unobtrusive Deferred Update Stabilization for Efficient Geo-Replication


Tese submetida para provas de mestrado em Engenharia Informática e de Computadores Instituto Superior Técnico, Universidade de Lisboa.

Abstract

Geo-replication is a requirement of most cloud applications. A fundamental problem that geo-replicated systems need to address is how to ensure that remote updates are applied and made visible to clients in a consistent order. For that purpose, both clients and servers are required to maintain some form of metadata. Unfortunately, there is a tradeoff between the amount of metadata a system needs to maintain and the amount of concurrency offered to local clients. Given the high costs of managing large amounts of metadata, many practical systems opt to serialise some updates, using some form of sequencer, which, as we will show, may significantly reduce the throughput of the system. In this paper we advocate an alternative approach that consists in allowing full concurrency when processing local updates and using a deferred local serialisation procedure, before shipping updates to remote datacenters. This strategy allows to implement inexpensive mechanisms to ensure system consistency requirements while avoiding intrusive effects on update operations, a major performance limitation. We have implemented and extensively evaluated our approach. Experimental data shows that we outperform sequencer-based approaches by almost an order of magnitude in the maximum achievable throughput. Furthermore, unlike proposed sequencer-free solutions, our approach reaches nearly optimal remote update visibility latencies without limiting throughput.

Publicações

Unobtrusive Deferred Update Stabilization for Efficient Geo-Replication
Chathuri Lanchana Rubasinghe Gunawardhana
MSc Thesis. Instituto Superior Técnico, Universidade de Lisboa.
July, 2016.
Available BibTeX, MSC Thesis, and extended abstract.
Unobtrusive Deferred Update Stabilization for Efficient Geo-Replication.
C. Gunawardhana, M. Bravo, and L. Rodrigues.
In Proceedings of the 2017 USENIX Annual Technical Conference, Santa Clara (CA), USA, July 2017.

Luís Rodrigues