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

Troubleshooting

Domain Validation

Table 3-1	Domain Validation Fallback Levels
	Type of SCSI	Bus Width	Data Transfer
			Rate (MB/s)
	Ultra160	Wide	160
	Ultra2 Wide	Wide	80
	Ultra2	Narrow	40
	Ultra Wide	Wide	40
	Ultra	Narrow	20
	Fast Wide	Wide	20
	Fast	Narrow	10
	Asynchronous	Narrow	<5
NOTE	The number of entries in Table 3-1 above is subject to change. We are
	providing it here to give you an example of how the fallback procedure
	works.

As mentioned earlier, Domain Validation tests are run on all targets on the SCSI bus, even those targets that do not have Ultra160 capabilities. Therefore, the starting point in Table 3-1 depends on the parameters that were negotiated for any particular target. In addition, since a SCSI bus can contain up to 15 targets, different SCSI parameters might be in effect at any one time on the bus (because Domain Validation is running on all of the targets at the same time).

If a fallback does occur and you fix the problem with the target hardware, you need to power cycle (power off and then power on) the target hardware and then run ioscan without the -koption (you can specify any other options, though). This restarts Domain Validation for that target and restores the negotiated parameters to the highest possible transfer rate and bus width. Next, look in the /var/adm/syslog.log file for any new “fallback” warning messages

86 Chapter 3