Abstract
& Conclusions -This paper investigates the (771, n) information dispersal scheme (IDS) used to support fault-tolerant distributed servers in a distributed system. In an (m, n)-IDS, a file M is broken into n pieces such that any m pieces collected suffice for reconstructing M. The reliability of an (m, n)-IDS is primarily determined by 3 important factors: • n = information dispersal degree (IDD), • n Im, = information expansion ratio (1ER), • PS = success-probability of acquiring a correct piece. It is difficult to determine the optimal IDS with the highest reliability from very many choices. Our analysis shows: • several novel features of (m, n)-IDS which can help reduce the complexity of finding the optimal IDS with the highest reliability; • that an IDS with a higher 1ER might not have a higher reliability, even when Ps -> 1. Based on the theorems given herein, we have developed a method that reduces the complexity for computing the highest reliability from, • O(v) [v -number of servers] to O(l) when the 'upper bound of the 1ER' = 1, or • O(v2) to O(l) when the 'upper bound of the 1ER' > 1. ©1997 IEEE.