Explicit constructions of MSR codes for the rack-aware storage model

Abstract

We consider erasure coding for a model of storage that assumes that nodes are organized into equally sized groups, called racks, such that repairing failed nodes is limited only by inter-rack communication, while transmission of data within a rack does not contribute to the repair bandwidth. We present explicit families of MDS array codes that support recovery of a single failed node from any number of helper racks using the minimum possible amount of inter-rack communication. One of our constructions also has the additional property of low access.Finally, we present a construction of scalar Reed-Solomon codes that support optimal repair for the rack-oriented storage model.