JBOD Development Based On The Double Expander Controller

This paper traces the storage device development in recent years. It spends a short span of30years from the computer’s hard disk, floppy disk, etc. to the current devices of hard disk cabinet, tape, disk array, NAS, SAN and so on a variety of large-scale storage device. SAS disk storage device based SAS Controller-SAS Expander-SAS/SATA technology is an important branch and already is used widely in recent years. In recent years along with the popularization of10G the network, the IP SAN storage has entered a rapid development period.The author studies SAS disk connection technology based SAS Controller-SAS Expander-SAS/SATA. JBOD based on double expander controller is a better solution because of higher reliability, the data security. JBOD based on double expander controller uses double expander as the core. The host server’s storage controller is redundant, combined with double expander design, so storage realizes redundancy and the large capacity.In this paper the author uses JBOD based on double expander controller system design and realization method for postgraduate study. The host server and JBOD are connected through the external SAS cable. JBOD based on double expander controller realize SAS signal propagation, using LSI’s SAS6G SAS2X36. Its realization process is as follows:First of all, the host server generated4SAS differential pairs, and they are connected to JBOD based on double expander controller.4SAS differential pairs are extended to32SAS differential pair through the redundancy of the expander controller. These signals are designed, and respectively connected hard disk as well as the next level of JBOD based on double expander controller. Secondly, cabinet achieve high reliability requirements through the hot plugging and redundancy design. Finally, JBOD based on double expander controller management functions are including hard disk indicating function, fan speed control function, fault alarm function.In this paper, JBOD based on the double expander controller has the characteristics of redundancy, hot swap function, data security, the number of cascaded JBOD.