The Design And Implementation Of SES For A RAID System

With the popularization of RAID technology, the practicability of automatic storage management and intelligent disk driver management become more and more important. The management of RAID system has two parts: one is SCSI Enclosure Services (SES), the other one is intelligent disk driver management.SCSI Enclosure Services is one of the SCSI standards for T10. SCSI devices reside in enclosures can provide power, cooling, and protection for the devices as well. Enclosure service is used for establishing the mechanical environment, electrical environment, and external indicators and controls for the proper operation and maintenance of devices within an enclosure. The RAID embedded system is comprised by hardware platform and bottom software platform. Hardware platform includes mainboard, subboard and backboard. Bottom software platform includes Board Support Package, Linux kernel and root filesystem. At last, backboard is the main hardware for SCSI Enclosure Services. Backboard is comprised of one W83791d and three Pcf8575, in which W83791d deals with the environment changes of enclosure and Pcf8575 is for managing the hard disk drivers.The intelligent disk driver management of RAID system includes two parts. One is automatic RAID configuration while the other is S.M.A.R.T technology. RAID updating disk drive configuration can automatically create a complete file configuration for the system, no matter at the startup phase or the runtime phase. The primary processes of the automatic RAID configuration are detecting whether it exists new disks insert, analyzing configuration information and applying conflict rules for any conflicts, rebuilding data and replacement the failed drive, updating configuration files and present it to host operating system. The automatic configuration mechanism is advantageous since it reduces the time cost of users'interaction and knowledge .S.M.A.R.T is the short form of self-monitoring, analysis and reporting technology. The integrated controller on the hard disk works with various sensors to monitor various aspects of the drive's performance. From this information it can determine whether the drive is running in a normal state or not, then it will transmit the available status information to software to probe the drive and check it.