一种基于阵列结构的4容错数据布局

An Array-Based Data Placement for Toleration on Four Failures

保证数据可靠性是存储系统设计的一个关键问题。EEOD码是一类3容错的数据布局,不允许任意4个磁盘同时故障。但随着存储系统中存储介质增大,数据损失概率也越来越大,为了提高系统可靠性,需要高效易于实现的存储容错技术。因此,对EEOD码进行扩展,增加了2列冗余校验列,提出一种新4容错HD-EEOD(Horizontal Diagonal EEOD)码,能容许任意4个磁盘同时故障,并保留EEOD具有简单几何结构编译码特性。基于码的几何结构,给出快速纠4错译码算法,算法易于软硬件实现。并对码的空间利用率、编译码效率进行分析,趋近于容4错编码的最优值,具有很好的性能和应用前景。

There is a key problem of building reliable data in the storage system.The EEOD code which is triple-erasure-correcting code can not tolerate any four failure.As the number of storage devices increases,the chance of losing data unacceptably increases due to storage devieces being down.Thus,A new coding scheme which is an extension of EEOD by adding to two parity columns are introduced.in this paper.The proposed code is used for tolerating four storage components,which is called the HD-EEOD code（Horizontal-Diagonal EEOD code）.The encoding and decoding performance of unique geometrical structure is retained.The novel efficient decoding algorithm based on geometrical structure is proposed for correcting various four node failures,which is realized easily.The HD-EEOD code is closer to the optimal performance including storage efficiency,encoding efficiency,decoding efficiency.Meanwhile,the regular structure of encoding and decoding algorithms makes it of practical for storage systems.