Troubleshooting
Domain Validation
TIP
Domain Validation
Domain Validation provides a way to automatically detect, and if necessary, compensate for hardware that is not performing to the optimal level. It does this by reducing the data transfer rate and bus width. This allows you to have data integrity even if data transfers cannot occur at the maximum data transfer rate supported by the HBA. If Domain Validation does reduce the rate and bus width, a message is generated so that you can correct the problem.
Domain Validation is automatically enabled for all SCSI devices on the bus, as long as you have set the HBA’s maximum data transfer rate to its maximum speed (160 MB/s for the A6828A). See “Maximum Data Transfer Rate” on page 45 for more information on setting the HBA’s transfer rate.
If necessary, you can disable Domain
Domain Validation runs each time the initiator device and target device negotiate the transfer rate and bus width. A few things that can cause this are as follows:
•A protocol violation or some other exception condition occurs on the SCSI bus.
•A SCSI device is powered on and then I/O occurs to that device. Things that Domain Validation might detect are as follows:
•Incorrect or improper SCSI bus termination (for example, a missing or bad terminator or an incorrect auto termination setting)
•Incorrect hardware configuration
•Cables with the wrong impedance
•Major cable errors (for example, a broken wire within a cable)
•SCSI device spacing problems
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