Distributed secure edge storage network utilizing cost function to allocate heterogeneous storage

A method of distributedly storing a file of size |F| in a system of networked storage nodes, the method comprising:

• selecting, by a system designer, a value Z that is a security parameter for distributedly storing the file in N storage nodes of the system, wherein Z<N and wherein the file and Z linear code keys are stored in N packets that are each stored in a different one of the N storage nodes, wherein at least two of the N storage nodes allocate different sizes of memory for storing the file, the N storage nodes being ordered from a largest storage capacity at a first storage node to a smallest capacity at an Nth storage node, the linear code keys stored in a first through Zth storage nodes and independent linear combinations of the linear code keys and partitions of the file stored in a Z+1th to Nth storage node, wherein the first through Z+1th storage nodes have a same allocated memory size of |PS_Z+1|, which is equal to a size of a largest of the partitions of the file, the largest partition of the file being stored on the Z+1th storage node;
• determining a lower bound on a cost by minimizing a cost function that includes N, |PS_Z+1|, |F|, Z, an initial data access cost CT, and a transmission and downloading cost Cd, the lower bound determining N*, which is an optimum value for N that minimizes the lower bound;
• initially allocating equal memory sizes from N* of the storage nodes with a largest available storage sizes to store the file and a set of linear code keys;
• based on determining more memory is required than available in the initial allocation of the N* storage nodes, iteratively determining a first cost of adding more storage nodes to the N* storage nodes and a second cost of allocating more memory from a subset of the N* storage nodes;
• and
• defining N≥N* based on a minimal cost determined from the iterative determinations, and storing the file and linear code keys in the N storage nodes.