Research On Device Driver And Online Capacity Expansion Technology In FC RAID

With the development of information technology, the demand on capacity is driven by explosively increasing information, and the demand on safety and performance of the storage system is becoming even more. Accordingly, how to increase the capacity of storage system with lesser cost, ensure data safety, and improve the speed is becoming more and more important in storage world.Based on the design of using FC (Fibre Channel) adaptor as the out-band channel and SCSI (Small Computer System Interface) adaptor as the device channel, the I/O performance of RAID (Redundant Array Of Independent Disks) storage system will be increased greatly.To support multi-disk-parallellism, LSI22320-R SCSI controller is chosen to work as the in-band interface. Based on the research of RAID working flow, developing platform and the Ultra320 SCSI protocol, the process and key technologies of designing and implementing LSI22320-R device driver is further analysed in detail. The test result proves that the LSI22320-R device driver using Message Passing technology can achieve significant performance improvement.Increasing data require much more online storage, and thus Online Capacity Expansion is implemented in FC RAID. It makes users increase the volume of the RAID system by adding new disks or using bigger disks to copy and replace the original disks, while they do not need to close and restart their system, backup their data, stop their using. Online Capacity Expansion Technology improves the expansibility and flexibility of RAID greatly.