Erasure-resilient codes having multiple protection groups

A computer-implemented process for constructing a basic Multiple Protection Group (MPG) Code for erasure encoding data having k original data chunks starting from a (n,k) Maximum Distance Separable (MDS) erasure code having n total chunks and (n−k) original parity chunks, comprising:

• organizing the k original data chunks into L number of protection groups, wherein L is greater than one;
• assigning the (n−k) original parity chunks into a global parity group and a local parity group;
• assigning one of the original parity chunks to each one of the protection groups to protect the data;
• splitting each of the original parity chunks in the local parity group into L number of local parities to generate the basic MPG Code;
• and
• using the computer to encode the data using the basic MPG Code.

A method for decoding data encoded using a basic Multiple Protection Group (MPG) Code having a plurality of hierarchical levels, comprising:

• determining at a bottom level of the plurality of hierarchical levels whether a first number of lost data chunks is smaller than or equal to a first number of available parity chunks;
• if the first number of lost data chunks is smaller than or equal to the first number of available parity chunks, then using a computing device to decode each of the lost data chunks and available parity chunks;
• designating each of the decoded lost data chunks and each of the decoded parity chunks as available;
• otherwise, if the first number of lost data chunks is greater than the first number of available parity chunks, then concluding that there are additional lost data chunks;
• and
• examining a next higher level of the plurality of hierarchical levels to see whether the lost data chunks can be recovered.