Dynamic Affinity Cluster Allocation in a Shared Disks Cluster

Abstract

A shared disks (SD) cluster couples multiple computing nodes for high performance transaction processing, and all nodes share a common database at the disk level. In the SD cluster, a front-end router selects a node for an incoming transaction to be executed. An affinity-based routing can increase the buffer hit ratio of each node by clustering transactions referencing similar data to be executed on the same node. However, the affinity-based routing is non-adaptive to the changes of the system load. This means that a specific node would be overloaded if corresponding transactions rush into the system. In this paper, we propose a new transaction routing algorithm, named Dynamic Affinity Cluster Allocation (DACA). DACA can make an optimal balance between the affinity-based routing and indiscriminate sharing of load in the SD cluster. As a result, DACA can increase the buffer hit ratio and reduce the frequency of inter-node buffer invalidations while achieving the dynamic load balancing.

Buffer management in a real-time shared disks cluster

“…Furthermore, the level of interference between nodes due to buffer invalidation will be reduced. This concept is referred to affinity-based routing [12,19]. To implement the affinity-based routing, we partition transactions into affinity clusters (ACs) according to their database references.…”

“…Table 2 shows simulation parameters. Many of their values are adopted from [8] and [12]. We assume that the GLM's CPU performs better than each node's CPU in order to prevent the GLM from being the performance bottleneck.…”

“…Yoo School of Electrical Engineering and Computer Science, Yeungnam University, Gyeongsan, South Korea e-mail: hrcho@yu.ac.kr A cluster is a collection of interconnected computing nodes that collaborate on executing an application. A shared disks (SD) cluster is a representative cluster architecture for high performance transaction processing [12,18]. The SD cluster allows each node to have direct access to all disks.…”