General structured voting: a flexible framework for modelling cooperations

International Journal of Parallel, Emergent and Distributed Sys

2014

Pessimistic quorum-based data replication strategies have strictly upper-bounded operation availabilities. The probabilistic relaxation of their strict consistency notion along different dimensions permits to overcome this upper-bound. The resulting probabilistic replication strategies allow the exploitation of the data consistency versus operation availabilities trade-off. In our approaches, we add a certain number of probabilistically intersecting quorums to the originally strictly intersecting partially ordered quorum system in order to 'closely conserve' its original characteristic behaviour. As one expects, the number and nature of probabilistic quorums added have a strong impact on the particular trade-off. We present two algorithms for the generation of probabilistic quorums based on input strict quorums. Furthermore, the order in which probabilistic and strict quorums are to be probed and used for executing operations is also very important. We relate three general strategies of ordering the probabilistic and strict quorums of those probabilistic quorum systems (PQSs), evaluate their impact on the data consistency versus operation availabilities trade-off and compare them in terms of this trade-off. The evaluation uses Markov chain-based steady-state analysis applied to a representative instance of PQSs with adequate partial orderings.

Section: System Modelmentioning

confidence: 99%

Relaxing data consistency along different dimensions for increasing operation availabilities

Lipskoch

International Journal of Parallel, Emergent and Distributed Sys

2014

“…Partially ordered quorum systems can be graphically specified and visualized by so-called voting structures as presented in [10]. In the following, for a more concise presentation, partially ordered quorum sets will be presented as lists (or sequences) of quorum sets with decreasing priority from left to right on the ordered elements.…”

Section: Definitions (Partially Ordered Strict Quorum Systems)mentioning

confidence: 99%

The Impact of Partial Orders among Strict and Probabilistic Quorums on the Data Consistency vs. Operation Availabilities Trade-Off

Iakab

International Symposium on Parallel and Distributed Processing With Applications

2010

Operation availabilities of pessimistic quorumbased replication strategies are strictly upper-bounded. Probabilistically relaxing their strict consistency notion permits to overcome this bound by introducing probabilistic data replication strategies. These strategies allow the exploitation of the data consistency vs. operation availabilities trade-off. In our approach, we add a certain number of only probabilistically intersecting quorums to the originally strictly intersecting partially ordered quorum system in order to "closely conserve" their original characteristic behavior. As one expects, the number and nature of probabilistic quorums added have a strong impact on the particular trade-off. But furthermore, it turns out that the order in which probabilistic and strict quorums must be probed is also very important. We relate two general strategies of ordering the probabilistic and strict quorums of those probabilistic quorum systems and evaluate their impact on the data consistency vs. operation availabilities trade-off. The evaluation uses Markov chain-based steady state analysis applied to representative instances of probabilistic quorum systems with the adequate partial orderings.

“…By simply redefining the specification, another data replication scheme is easily modeled. Conceptually, a tVS is a voting structure [15] transformed from a directed acyclic graph into a tree graph. Therefore, the universality of voting structures for specifying (static) data replication schemes is also given for tVSs.…”

Section: Fig 1 Process Template Subnetmentioning

confidence: 99%

A General Approach to Analyzing Quorum-Based Heterogeneous Dynamic Data Replication Schemes

Storm

Distributed Computing and Networking

2008

Abstract. Choosing a strict quorum-based data replication scheme for a particular application scenario in the decision space spawned by static and dynamic, unstructured and structured, homogeneous and heterogeneous data replication schemes is a crucial decision w.r.t. the resulting quality properties of the distributed system and therefore needs a careful evaluation. To date, the analysis of data replication schemes is limited to only a very specific subclass, namely to homogeneous unstructured schemes: Existing approaches are specifically tailored towards a particular instance of a homogeneous unstructured data replication scheme. In this paper, we present a novel approach to the analytical evaluation of strict quorum-based data replication schemes by means of a compositional GSPN system model. This model allows to evaluate structured and moreover heterogeneous (as well as unstructured and homogeneous) dynamic data replication schemes and also applies for static schemes. Because of being compositional, different data replication schemes can be easily evaluated with the same general system model.