HP A6829A PCI Dual Channel Ultra160 SCSI Host Bus Adapter Service and User Guide (May 2003)

Troubleshooting
Domain Validation
Chapter 386
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 -k option (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
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