By default, Linux assigns host numbers to HBAs somewhat arbitrarily. In practice, it's fairly predictable as long as you don't change anything -- Linux assigns them sequentially starting at zero in the order in which it discovers them, which is controlled first by the order in which Linux initializes the corresponding HBA driver.
But you can control it a little. The 'scsihosts' module parameter of the SCSI midlayer driver scsi_mod reserves host numbers for specific HBA drivers. It looks like "scsihosts=aic7xxx,aic7xxx,qla1280". That means to reserve host numbers 0 and 1 for the aic7xxx driver and 2 for qla1280. The two reserved for aic7xxx are assigned in the order that the aic7xxx driver registers them, which is ordinarily the order in which the aic7xxx driver detects them. I don't think there's usually a way to control that, but it should be repeatable as long as the hardware configuration stays the same. But it's generally not good to rely on the hardware configuration staying the same. Some day, one card will be broken or temporarily removed, and that will change the host number of the other one. As with other SCSI numbering (LUNs, Linux device numbers), you normally don't try to prescribe which numbers go to which equipment, but rather discover afterward -- proc/scsi/hba_name/host_number. The identifying information is dependent on the particular HBA type and driver, and sometimes doesn't exist. - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
