基于非均匀循环编码的分组修复码构造

考虑到实际分布式存储系统中节点故障情况的多样性，该文提出一种基于非均匀循环编码的分组修复码(GRC-NCC)，使高故障率节点得到更有效的保护。具体地，根据节点故障率对存储节点进行非均匀分组，将数据块依次存入长度递增的节点分组，再使用跨条带循环编码的思路生成组编码块和全局校验块。性能分析以及实验仿真表明，GRC-NCC虽然具有高于RS码的存储开销，但与RS码和重叠分组修复码相比，该方法在故障节点修复过程中具有较低的修复带宽开销和修复局部性，且在多节点故障修复过程中性能更优，容错性更好。

Construction of Group Repairable Codes Based on Non-Uniform Cyclic Coding

Considering the diversity of node failures in the actual distributed storage systems, group repairable codes based on non-uniform cyclic coding (GRC-NCC) are proposed in this paper, to protect the nodes with high failure rate more effectively. Specifically, storage nodes are grouped non-uniformly according to the node failure rate, data blocks are sequentially stored into node groups with increasing length, and then group coding blocks and global check blocks are generated by using cross-band cyclic coding. Performance analyses and experimental simulations show that GRC-NCC has lower repair bandwidth overhead and repair locality during repairing the failed nodes, and better fault tolerance in the process of multi-node fault repair compared with reed-solomon (RS) codes and rotated group repairable codes (RGRC), although GRC-NCC has higher storage overhead than RS codes.