HP I Dual Channel Ultra160 SCSI Host Adapter A6829A manual Setting Scsi IDs

Installing the A6829A Adapter

Specifying SCSI Parameters

SCSI IDs

You must assign a separate SCSI ID (0 through 15 for a 16-bit SCSI bus) to the SCSI host bus adapter (HBA) and each SCSI device. The priority of the device on the SCSI bus is determined by the SCSI ID of the device. The order of SCSI ID priorities (from highest to lowest) is 7, 6, 5, 4, 3, 2, 1, 0, 15, 14, 13, 12, 11, 10, 9, and 8. A device with SCSI ID 7 has the highest priority, and one with SCSI ID 8 has the lowest.

When you are assigning SCSI IDs, HP recommends you to give the SCSI HBA higher priority than the other SCSI devices on the bus. SCSI ID 7 is the preset SCSI ID for the A6829A SCSI HBA, thereby giving it the highest priority on the SCSI bus. Set each of the other SCSI devices on the bus to one of the remaining SCSI IDs.

In a multi-initiator (High Availability [HA]) configuration, multiple SCSI HBAs are connected to the same SCSI bus. For such configuration, the SCSI HBA that carries most of the traffic must be assigned a SCSI ID of 7 (highest priority). Later, you must change the SCSI ID of each of the remaining SCSI HBAs on the bus from the preset setting (7) to the next highest priority remaining SCSI IDs (for example, 6, 5, 4, and so on).

If you plan to boot your system from a hard disk drive on the SCSI bus, you must assign that drive the next highest priority unassigned SCSI ID. If there is only one SCSI HBA (SCSI ID = 7), the hard disk drive will be assigned a SCSI ID of 6. If there are multiple SCSI HBAs, the hard disk drive will be assigned the next highest priority SCSI ID available after all of the SCSI HBAs have been assigned higher priority SCSI IDs.

Setting SCSI IDs

To set the SCSI ID of the A6829A HBA, see “Setting and Confirming

SCSI Parameters” on page 90.

The peripheral device SCSI IDs are usually set with jumpers or a switch on the peripheral. Refer to the peripheral manufacturer’s instructions to determine the ID of each device and how to change it.

IMPORTANT You must not have duplicate SCSI IDs on a SCSI bus; the system may hang or crash if you have duplicate SCSI IDs on the bus.

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