Allocation for Heterogeneous Storage Nodes

Storage allocation, meaning the way that a chunk of data is stored over a set of storage nodes, affects different performance measures of a distributed storage system (DSS). In this work, we study the storage allocation problem for a DSS where nodes have different storage capacities. To this end, we first introduce the notion of k-guaranteed allocations referring to allocations where the data can be recovered by accessing any arbitrary set of k storage nodes. We then find the necessary conditions for an allocation to be k-guaranteed considering the limit on the individual node capacities and the overall storage budget. Using these conditions, an iterative algorithm is developed to find k-guaranteed allocations, if feasible.