CAJ | 학술논문

当前常使用多个云共同存储数据，以保证用户数据可靠性。为减少存储成本和修复带宽，提出了一种使用功能性修复再生码（FRC）将数据编码为多个数据块，并分布于不同的云中的方法。该方法减少了多个云中单个云发生数据丢失时需要从网络上传输的数据量，并减少了修复成本，已成功地应用于所构建的云存储系统Ustor中。实验表明：与不编码比较，冗余编码给系统增加了5%~10%的响应时间开销，但可保障节点失效；FRC码编、解码和修复速度与里德-所罗门（Reed-Solomon或RS）码基本相当，256 MB大小文件编码时间差距在0.5 s以内；FRC码修复时与传统的RS码相比减少了25%以上需要下载的数据量。
당전상사용다개운공동존저수거，이보증용호수거가고성。위감소존저성본화수복대관，제출료일충사용공능성수복재생마（FRC）장수거편마위다개수거괴，병분포우불동적운중적방법。해방법감소료다개운중단개운발생수거주실시수요종망락상전수적수거량，병감소료수복성본，이성공지응용우소구건적운존저계통Ustor중。실험표명：여불편마비교，용여편마급계통증가료5%~10%적향응시간개소，단가보장절점실효；FRC마편、해마화수복속도여리덕-소라문（Reed-Solomon혹RS）마기본상당，256 MB대소문건편마시간차거재0.5 s이내；FRC마수복시여전통적RS마상비감소료25%이상수요하재적수거량。
To ensure reliability of user’s data, multiple clouds are responsible for storing the data. For purpose of mini-mizing storage cost and repair bandwidth, a method of utilizing functional regenerating codes(FRC) to encode data to several blocks, which are further distributed to different clouds, was proposed. In this way, amount of data downloaded through the network when data loss happens in a single cloud is cut down, and repair cost is cut down as well. This method was successfully applied in a cloud storage system Ustor. Observations can be drawn from the experimental re-sults:first, erasure coding guarantees data reliability, increasing 5%~10%response time compared with non-coding;sec-ond, speed of FRC encode, decode and repair are a little slower than Reed-Solomon(RS) code, and the time gap of en-coding 256MB by two codes is less than 0.5 seconds;third, compared with traditional RS codes, FRC reduces more than 25%data amount needed to download during a repair in the experiment.