7.13.4 SCSI Controller Failures

To check whether the main logic board SCSI controllers are defective, test the drive response to the probe-scsi command. To test additional SCSI host adapters added to the system, use the probe-scsi-all command. You can use the OBP printenv command to display the OpenBoot PROM configuration variables stored in the system NVRAM. The display includes the current values for these variables as well as the default values. See "7.12.2.3 OBP printenv Command" for more information.

1. At the ok prompt, type:

   ok probe-scsi

   If a message is displayed for each installed disk, the system SCSI controllers have successfully probed the devices. This indicates that the main logic board is working correctly.

2. If a disk does not respond, make sure that each SCSI device on the SCSI bus has a unique SCSI target ID.

3. If the problem persists, replace the unresponsive drive.

4. If the problem remains after replacing the drive, replace the main logic board.

5. If the problem persists, replace the associated SCSI cable and backplane.