New Design and Analysis of Error-Resilient LRCs for DSSs with Silent Disk Errors

Recently, erasure coding techniques are considered as essential schemes for the reliability of the modern distributed storage systems (DSSs) with the frequent node-level failure. Especially, locally repairable codes (LRCs) are widely adopted by the practical advantage of reducing the latency for repair process. However, recent researches show that many cases for system failure are also originated from the silent disk errors. For the conventional LRCs with low error correction capability, repair process from erasure coding can propagate the silent errors and thus, the DSSs become more vulnerable compared to the cases only with node failure. Therefore, we propose a mean time to data loss (MTTDL) from the modified Markov chain model in order to evaluate effects by silent disk errors. Also, new design of binary error-resilient locally repairable codes (ER-LRCs) with high error and erasure correction capabilities are proposed, which have larger values of bit-wise minimum Hamming distance than the existing LRCs. Here, ER-LRCs can be constructed by modifying the parity check matrix from well-known optimal binary and nonbinary LRCs. From the numerical analysis using the proposed Markov model with empirical parameters, it is shown that the proposed ER-LRCs have better MTTDL values when compared to the existing LRCs.