EH-Code: An Extended MDS Code to Improve Single Write Performance of Disk Arrays for Correcting Triple Disk Failures

Abstract

In the information explosion era, with the sharp increasing requirements of storage devices, concurrent multiple disk failures are not rare. In large data centers, erasure code is one of the most efficient ways to protect user data with low monetary cost. One class of erasure codes is called Maximum Distance Separable (MDS) codes, which aims to offer data protection with minimal storage overhead. However, existing Triple Disk Failure Tolerant arrays (3DFTs) based on MDS codes suffer from low single write performance, because the corresponding codes have high computational cost and low encoding performance. To address this problem, in this paper, we propose a novel MDS coding scheme called EH-Code, which is an extension of H-Code. It has three different parities, horizontal, diagonal and anti-diagonal parities, which can tolerate concurrent disk failures of any triple disks. Our mathematical analysis shows that EH-Code offers optimal storage efficiency and encoding computational complexity. Specifically, compared to STAR code, Triple-Star code and Cauchy-RS codes, EH-Code can improve the single write performance by up to \(16.13\,\%\), \(14.53\,\%\) and \(26.27\,\%\), respectively.