Study On Data Recovery Technology By Erasure Code In Optical Library

With the coming of big data era, data arching is becoming more and more important for enterprise. Because of its low price, the optical library has developed so quickly in recent years as a kind of mass storage device. With the increasingly complexity of application environment, the reliability of storage system such as optical library was given a severe challenge. As the main method of fault tolerance of storage system, erasure codes are getting more and more attention.Through the analysis of the specific requirements of optical library which needs high fault tolerance and high space utilization, we studied the fault tolerance technologies for multiple failures of optical library and design the optical library redundancy subsystem with high fault tolerance.The subsystem is composed of five modules, basic encoding module generates redundancy optical disc from data optical disc. The basic decoding module rebuilds failed optical disc when disc failures occurs. With the codec segmentation module, a encoding or decoding process can be divided into multiple stages. Based on the research for matrix scheduling algorithm, the scheduling optimization algorithm can reduces the total number of exclusive or operations, fundamentally. With the Linux thread pool technology, the encoding and decoding performance has been improve effectively.The testing show that the scheduling optimization algorithm can effectively reduce the total number of exclusive or operations, and the optimization ability is about 2 times of the original one when encoding, and is about 1.7 times when decoding.