Modified Generalized Integrated Interleaved Codes for Local Erasure Recovery

Locally recoverable codes allow erasures to be recovered from a portion of codeword symbols and are essential to address the high reliability and performance requirements of modern hyper-scale distributed storage systems. Generalized integrated interleaved (GII) codes create redundancy sharable by the interleaves, and hence reduce the overall redundancy for achieving target reliability. However, all interleaves need to be read in order to make use of the shared redundancy. In this letter, GII codes are modified to improve the locality. Without sacrificing the erasure correction capability, the proposed scheme accesses much fewer interleaves when only a small number of extra erasures need to be recovered using the shared redundancy, which happens in most cases. As a result, the average locality is greatly improved. Compared to existing local erasure recovery schemes, the modified GII codes achieve a good tradeoff on locality and correction capability.