To simplify our analysis, we do not address disk I/Ointerference, which occurs in the following cases: (i) inscattered repair, an existing healthy node reads a locally storedchunk while writing the repaired chunk for another stripe, and(ii) in hot-standby repair, a hot-standby node writes the chunksfrom both migration and reconstruction. We also assume thatthe computational costs of coding operations are negligiblecompared to disk I/Os and network transmission [16].