A New Placement-Ideal Layout for Multiway Replication Storage System

Technology trends are making sophisticated replication-based storage architectures become a standard commercial practice in today´s computing. Existing solutions successfully developed optimal and near-optimal parallelism layouts such as declustered parity organizations at small-scale storage architectures. There are very few studies on multiway replication-based storage architectures that are significantly different from parity-based storage architectures. It is difficult to scale up to a large size because current placement-ideal solutions have a limited number of configurations. In this paper, we retrofit the desirable properties of optimal parallelism definitions in parity architectures for replication architectures, and propose a novel placement-ideal data layout-shifted declustering. Shifted declustering layout obtains optimal parallelism in a wide range of configurations, and obtains optimal high performance and load balancing in both fault-free and degraded mode. Our theoretical proofs and comprehensive simulation results show that shifted declustering is superior in performance, load balancing, and reliability to traditional layout schemes such as standard mirroring, chained declustering, group-rotational declustering, and existing parity layout schemes PRIME and RELPR.