San-based Mass Storage System Design And Realization

With the rapid growth of information and the improvement of the importance and safety of information, the methods and means of the information management will have to face the challenges of higher demand. It has become a pressing and important issue that how to quickly meet the growing demand for information rising and efficient management and maintenance of information resources.As a network storage solution, SAN was based on to achieve large-capacity, high-performance storage systems, which have become a hot research point in the world. As the most critical part of the storage management system and the core of storage nodes, RAID does not always provide us with satisfied performance:1. In RAID 5, the "small piece write" has a lower operating efficiency, as well as, the small piece write will seek path and position continually, which is inconsistent with the disk properties. Put all bad together, the process of "small piece write" was made even more slowly. And, the single I/O request response time of RAID 5, which was concerned by "small piece write", is four times long to RAID 0. Because the I/O access patterns of the database applications and the file system applications contain a large number of "small piece write" operation, the high performance of "small piece write" has an important influence on the storage management system.2. When system is reconstructing, all of the normal disks will be in overload state, so the probability of another disk going wrong is increased. Once another disk is fault, the data of the storage management system will be lost forever and can not be recovered. Therefore, it is the important issue, which must be considered when designing the kenerl processing module of RAID, that how to revover to normal mode from degrade mode as soon as possible, at the same time, ensuring the data consistency and the I/O request of the host responsed quickly.Based on the deeply study of the variety key technologies of RAID, the key technology of RAID 50, "small piece write" optimization strategy, data reconstruction optimization algorithm were carried out, and a high-performance disk array system which has a dual-processor, high-capacity CACHE and high-performance was designed and realized. Finally, through running plenty of test cases, it is proved that the design of the system is successful overall, combined with RAID 0 and RAID 5 technology, the design model of RAID 50 increases the concurrency of I/O access. The "small piece write" optimization strategy improves the process speed and bandwidth of random/sequential small piece write. Data reconstruction optimization algorithm reduces the demand for memory resources of the reconstruction process, and takes full use of system idle bandwidth, which makes reconstructiong and response user faster. Therefore, the mass storage-management system based on SAN fully takes the advantages of a dual-processor and high-capacity performance of CACHE, it can handle and response the host request rapidly, response and execute variety of disk operation, and it has higher tolerant capacity, usability and stability, achieves the demand of a high-performance enterprise-class storage management systems.