SCSI Bus Configuration Requirements

SCSI buses must adhere to a number of configuration requirements in order to operate correctly. Failure to adhere to these requirements will adversely affect cluster operation and application and data availability.

The following are SCSI bus configuration requirements:

• Buses must be terminated at each end. See the Section called SCSI Bus Termination for more information.

• Buses must not extend beyond the maximum length restriction for the bus type. Internal cabling must be included in the length of the SCSI bus. See the Section called SCSI Bus Length for more information.

• All devices (host bus adapters and disks) on a bus must have unique SCSI identification numbers. See the Section called SCSI Identification Numbers for more information.

• The Linux device name for each shared SCSI device must be the same on each cluster system. For example, a device named /dev/sdc on one cluster system must be named /dev/sdc on the other cluster system. One way to ensure that devices are named the same is by using identical hardware for both cluster systems.

Use the system's configuration utility to set SCSI identification numbers and enable host bus adapter termination. When the system boots, a message is displayed describing how to start the utility. For example, the utility will prompt the user to press [Ctrl]-[A], and follow the prompts to perform a particular task. To set storage enclosure and RAID controller termination, refer to the vendor documentation. See the Section called SCSI Bus Termination and the Section called SCSI Identification Numbers for more information.

See http://www.scsita.org and the following sections for detailed information about SCSI bus requirements.