A Research Of RAID1Technology Based On SSD Cache

With the rapid development of high technology, solid-state disk (SSD) is introducedinto the storage system, its high performance, low power cost can meet the needs ofmodern data storage very well and it plays a very good role in solving the bottlenecks oftraditional disk performance. But SSD is expensive and its capacity is small, it cost toomuch to replace traditional disk completely, most enterprises can not afford. In order toimprove system performance and reduce the cost of storage systems, enterprises generallyuse SSD as a hierarchical storage medium or as a disk cache, this solution is a hotresearch.After analyzing the existing technology of SSD used as cache, designs a schemewhich not only takes advantage of SSD performance and reduces system cost, but alsoensures the storage system reliability. The scheme takes advantage of SSD’s I/O featureand then stores hot data in SSD, leaving cold data in disks. In order to ensure thereliability of hot data and cold data, it stores two copies of data in disk, which both includehot data and cold data copy, with the replacement of the SSD cache automatically shifting.In the system, all the disks are organized like RAID1. The scheme designs three differentdata layout, which are applicable to different scenes.The system is implemented with simulated methods, and made a compared testamong different data layout. The results confirm their application scenarios. And thencompare to the following designs: SSD used as cache with write through and multipleSSDs used as multiple data copies. The results show that our design is able to get a goodbalance between performance and price cost, and ensure system reliability.