Research On The Key Technology In Solid State Storage Array

Recently, flash memory,as a more mature solid-state storage media, has many attractive features such as h igh performance, small size, light weight, low po wer consumption,has thus been adopted in enterprise servers and high perfor mance computing environments and brought opportunities and challenges to the storage system in high-performance computing.. Meanwhile, RAID( Redundant Array of Independent Disks) is a widely used data storage t echnology, which can im prove I/O performance through data segmentation and parallel access and the availability and reliability by using error correcting technology. Therefore, building storage array based on flash memory becomes an efficient approach to build large-scale storage system with high perfomance and reliability. If we just change the mechanical disks to flash memory in a RAID system several s erious problems will occure, such as the small write problems, the wear leveling between ch ips. Therefore, this thesis focuses on design and implementation of solid-state storage array with high performance and reliability, based on the existing flash and storage array technologyThe main work is as follows:(1) Investigate flash technology and flas h-based RAID m echanism. We have analysed the existing flash m emory technology including the Flas h Translation Layer(FTL) and cache management strategies. the key technologies of building RAID system based on flash memory is also investigated.(2)Design a PCI-E based solid-state storage array card. The array card uses a PCI-E interface with high speed data transmission rate to communicate with the host. It has 16 channels and can para llel manage 64 f lash chips. The PCI-E based solid-state storage array card provides higher perform ance and reliability than SAS/SATA based solid-state storage array card. The device I/ O throughput of this card is 524 K, and the I/O bandwidth is 2.83GB/s.(3)Propose a cache-based restructur able RAID mechanism(CBR-RAID). CBR-RAID uses a Storage Class Memory(S CM) as a cache. Under the idea of RAI D restructuring, CBR-RAID restructures the data replaced from cache into RAID stripein sequence. CBR-RAID can overcom e the sm all write prob lem of traditional RAID mechanism, and improve the performance and the lifetime of solid-state storage array. Meanwhile, it can also addressing the wear leveling problems between different chips in the array. Sim ulation results show that CBR- RAID can reduces the read and write response time, the count of erase operations and the frequency of garbage collection in solid-state memory array.