Research And Implementation Of Dual-Controller RAID System

With the rapid development of information construction around the world, make largeamount of data, which need special storage system to provide a stable, reliable, safe datastorage service. Dual-Controller RAID system adds the hardware level redundant relativeto Single-Controller RAID system, so it has the level of disk and controller high stabilityand reliability. It can satisfy the requirements of storage service stability of higher industry.Relative to Single-Controller RAID system, the difficulty of Dual-Controller RAIDsystem is fault detection, fault processing and the consistency between the controllers.The Dual-Controller RAID system which is research and implement using the specialheart module between the controllers for communication which include heart beat packet,status notification etc. So when the system is running, one controller is always getting themirror controller’s state, it helps for fast detected the fault when the mirror controller isfault. The heart beat modules use fixing communication agreement when the system isstarting, fault recovering, and fault processing for setting the controller working mode,that make the system work normally.The CACHE module needs to maintain two types of data which are maintainCACHE and MIRROR for making sure the data in the CACHE of two controllers isconsistency. The system uses the synchronization of written way when processing therequest of write type, it returns the request when two controllers are all writing data over.When one controller is fault, the data of MIRROR will change to the data of CACHE,continue to service the data request. When the controller is recovery, the CACHE of twocontrollers should make the data consistency before working.We use Dual-Controller RAID system and Single-Controller RAID system doing acontrast test, and test the reliability of Dual-Controller RAID system. The result shows theperformance of Dual-Controller RAID system is almost the same with theSingle-Controller RAID system, and the Dual-Controller won’t loss the data and cancontinue to provide data services.