利用空闲空间抗两个磁盘失效的RAID5阵列算法

传统的RAID5阵列存储算法只能保证一个磁盘失效的时候重建数据，本文设计了一种新的RAID5阵列算法，包括储存算法和重建算法，使得在磁盘在使用少于一半空间的情况下，即使有两块磁盘失效，也可以重建数据，即抗2个磁盘失效失效，而当使用大于一半空间的时候，恢复使用传统算法进行存储重建。比较于传统算法，新的算法使RAID5阵列的可容忍磁盘失效数量提高50％，可容忍失效的己存储数据块量提高25％，磁盘空间利用率提高25％。

A RAID5 array algorithm using free space to achieve anti-two- disks-failure

Traditional RAID5 array algorithm can only guarantee rebuilding data when only one disk failure .we design a new RAID5 array algorithm, including storage algorithm and rebuild algorithm, in the case of less than half array space left, we can rebuild the data when two disk failure, namely anti-two disk failures ; and in the case of more than half of the space, use conventional RAID5 array algorithms for storage and rebuilding. Compared to the old one, the new algorithm makes the tolerate number of disk failure of RAID5 array increase by 50%,number of tolerated stored data blocks loss increased by 25%, disk space utilization by 25%.