III. MATHEMATICAL ANALYSISWe conduct simple mathematical analysis to provide preliminary insights into the performance gain of the optimalpredictive repair over the conventional reactive repair in alarge-scale storage cluster.General formulation: We first provide a general formulationthat addresses the performance of both reactive and predictiverepair strategies in both scattered and hot-standby repair scenarios, and later extend the formulation for different scenarios.Let M be the total number of nodes in a storage cluster andU be the total amount of chunks of the STF node that arerepaired. Let x be the amount of chunks being repaired bymigration; hence, U Ux is the amount of chunks being repairedby reconstruction.