HP I Dual Channel Ultra160 SCSI Host Adapter A6829A manual Domain Validation

Troubleshooting

Domain Validation

(shown earlier in this section). If the problem was fixed properly and Domain Validation is at the correct level, you will not see any new warning messages.

As an example, if the parameters originally negotiated during the normal SCSI initiator/target communications are equivalent to Ultra160, but Domain Validation determines that the SCSI bus or the target cannot support that data transfer rate, Domain Validation falls back to Ultra2 Wide. Then, Domain Validation repeats its test. If the bus or target still cannot support the transfer rate, Domain Validation falls back another level, to Ultra2 Narrow. As long as failures occur, fallback continues, one level at a time, until the last level in Table 3-1 (Asynchronous) is reached. (Note that a “fallback” warning message—shown earlier in this section—is not generated each time Domain Validation falls back a level, but only when it successfully settles at a level.) If the last level is reached and a failure still occurs, the following message is written to the /var/adm/syslog.log file:

SCSI:Ultra160 SCSI Adapter at hw_path: Error: The domain validation test for target target_ID determined that communication may not be possible to this target. Verify the hardware at the next opportunity.

To be able to restore communication to the target hardware, you must fix the problem with the target, power cycle (power off and then power on) the target, and then run ioscan without the -koption to restart Domain Validation and renegotiate the parameters for that target. Next, you need to check /var/adm/syslog.log for any new “fallback” warning messages. The lack of new “fallback” messages means you successfully fixed the problem, and the data transfer rate and bus width are at the correct levels.

Note that when a Domain Validation test succeeds, no message is written to the /var/adm/syslog.log file. The reason is that this would generate a large volume of messages, especially on a system that is used heavily. Not only would this make the file very large, but the more important warning and error messages would not be easy to see.

In addition, a SCSI selection timeout—when a target device does not respond to selection within a certain length of time—will terminate a Domain Validation test on a target, and the target will be considered to be non-existent. This is so that a bus scan or system boot will not be extended by Domain Validation waiting several times for a target that does not exist.

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