Improving the scalability of cloud-based resilient database servers

Many rely now on public cloud infrastructure-as-a-service for database servers, mainly, by pushing the limits of existing pooling and replication software to operate large shared-nothing virtual server clusters. Yet, it is unclear whether this is still the best architectural choice, namely, when cloud infrastructure provides seamless virtual shared storage and bills clients on actual disk usage. This paper addresses this challenge with Resilient Asynchronous Commit (RAsC), an improvement to awell-known shared-nothing design based on the assumption that a much larger number of servers is required for scale than for resilience. Then we compare this proposal to other database server architectures using an analytical model focused on peak throughput and conclude that it provides the best performance/cost trade-off while at the same time addressing a wide range of fault scenarios

A Metaprotocol Outline for Database Replication Adaptability

Abstract. Database replication tasks are accomplished with the aid of consistency protocols. Commonly, proposed solutions use a single replication protocol providing just one isolation level. The main drawback of this approach is its lack of flexibility for changing scenarios –i.e. workloads, access patterns... – or heterogeneous client application requirements. This work proposes a metaprotocol for supporting several replication protocols which use different replication techniques or provide different isolation levels. With this metaprotocol, replication protocols can either work concurrently with the same data or be sequenced for adapting to changing environments. In this line, the use of a load monitor would enable the best choice for each transaction, selecting the most appropriate protocol according to the current system characteristics. This paper is focused on outlining this metaprotocol design, establishing the metadata set needed and the required interaction between the main database replication protocol families.