07/01/1990 09:00 AM
Computer Science
Data replication has been widely used to build resilient data objects. These objects normally consist of several replicas stored in stable storage and a replication control protocol managing these replicas. Replicated data objects incur a significant penalty resulting from the increased number of disk accesses. We propose several protocols that improve performance while not significantly impacting the availability of the replicated data object. Our replicated data objects consist of several memory-resident replicas and one append- only log maintained on disk. We analyze, under standard Markovian hypotheses, the availability of these data objects when combined with three of the most popular replication control protocols: *available copy* (AC), *majority consensus voting* (MCV), and *dynamic-linear voting* (DLV). We show that replicated objects consisting of n memory-resident replicas and a disk-resident log have almost the same availability as replicated objects having n disk-resident replicas.