Optimal binary vote assignment for replicated data

Data replication can be used to improve the availability of data in a distr ibuted database system. In such a system, a mechanism is required to mainta in the consistency of the replicated data. Weighted voting is a popular sol ution for maintaining the consistency. The performance of a voting system i s determined by the vote assignment. It was shown in previous studies that finding the optimal solution among nonnegative integer vote assignments req uires O(2(N2)) time. So it is not suitable to find the optimal integer vote assignment (OIVA) for large systems. In this paper, cue propose the optima l binary vote assignment (OBVA) considering only binary vote assignments. I t is shown that OBVA can achieve nearly the same availability of OIVA. On t he other hand, OBVA requires only O(N-2) time, which is preferred for large systems. (C) 2000 Elsevier Science Inc. All rights reserved.