D.4. SCSI Bus Length

A SCSI bus must adhere to length restrictions for the bus type. Buses that do not adhere to these restrictions do not operate properly. The length of a SCSI bus is calculated from one terminated end to the other and must include any cabling that exists inside the system or storage enclosures.

A cluster supports LVD (low voltage differential) buses. The maximum length of a single-initiator LVD bus is 25 meters. The maximum length of a multi-initiator LVD bus is 12 meters. According to the SCSI standard, a single-initiator LVD bus is a bus that is connected to only two devices, each within 0.1 meter from a terminator. All other buses are defined as multi-initiator buses.

Do not connect any single-ended devices to an LVD bus; doing so converts the bus single-ended, which has a much shorter maximum length than a differential bus.