Patent ID: 8856619

Claim:
A method performed by one or more computers, the method comprising: receiving (n−f) data chunks for storage across n groups of storage nodes, wherein n and f are greater than or equal to two, and wherein (n−f) is greater than or equal to one; generating (f−1) error-correcting code chunks using an error-correcting code and the (n−f) data chunks; storing the (n−f) data chunks at a first group of storage nodes; and storing each data chunk of the (n−f) data chunks at a respective second group of storage nodes of a plurality of second groups of storage nodes and storing each code chunk of the (f−1) code chunks at a respective third group of storage nodes of a plurality of third groups of storage nodes, wherein each second group of storage nodes and each third group of storage nodes is distinct from each other and from the first group of storage nodes; wherein: each of the n groups of storage nodes corresponds to one of n vertices in a complete block design of size n, the complete block design including ( n 2 ) = n × ( n - 1 ) 2 blocks of vertices, the first group of storage nodes corresponding to a home vertex; each data chunk corresponds to a respective one of the blocks of vertices having the home vertex; each data chunk corresponds to a respective one of the blocks of vertices having a vertex corresponding to the respective second group of storage nodes; and storing the data chunks includes storing each data chunk at the group of storage nodes corresponding to the vertex in the block corresponding to the data chunk.