HP Surestore Disk Array FC60 HP SureStore E Disk Array 12H User's and Service - Page 99

Concepts and Management Disk Array Hardware SCSI Bus Topology The array controller communicates externally with the host over a fast-wide, differential SCSI bus. Each array controller is addressed by the host as a separate SCSI target; therefore, they must each have different addresses if they are connected to the same SCSI bus. The array controller SCSI address and all other SCSI operating parameters are set programmatically from the control panel on the disk array enclosure, or using the host software utility. There are no hardware jumpers on the array controller. Internally, the array controller communicates with the disks over four separate single-ended (SE) SCSI buses. Disk SCSI addresses and all other operating parameters are set internally by the disk array controller. There are no hardware jumpers on the disk modules. To ensure optimum performance, the disk modules should be distributed equally across the internal SCSI busses. This is accomplished by simply making sure the disk modules are installed in the enclosure in the correct order-left-to-right, top-to-bottom. Overloading one or two of the internal SCSI busses can impact throughput and decrease performance. Figure 24. SCSI Bus Details 99 Concepts