Distributed storage layout schemes

When distributing data across several nodes, two different approaches exist. The first one consists in distribution of the data object itself e.g. in striping. The second approach is aggregation of local storages, whereby each data object is assigned to a home storage node. From the viewpoint of fault-tolerant data layouts, these schemes seem to be similar. In both cases the addition of parity, e.g. RAID level 3, level 5 or Reed-Solomon codes provide tolerance against node failures. A closer look shows differences in reachable access rates, needed number of messages and recovery cost. In this paper we compare both approaches and provide a method for self-reconfiguration. The transformation from a parity grouping layout to a striping layout is shown to be feasible for stepwise and concurrent operation during data access.