Compaq AA-RHGWB-TE manual Scsi Bus Adapter Restrictions, KZPSA-BB Scsi Adapter Restrictions

2.4 SCSI Bus Adapter Restrictions

To connect a member system to a shared SCSI bus, you must install a SCSI bus adapter in an I/O bus slot.

The Tru64 UNIX operating system supports a maximum of 64 I/O buses. TruCluster Server supports a total of 32 shared I/O buses using KZPSA-BB host bus adapters, KZPBA-CB UltraSCSI host bus adapters, or KGPSA Fibre Channel host bus adapters.

The following sections describe the SCSI adapter restrictions in more detail.

2.4.1 KZPSA-BB SCSI Adapter Restrictions

KZPSA-BB SCSI adapters have the following restrictions:

•The KZPSA-BB requires A12 firmware.

•If you have a KZPSA-BB adapter installed in an AlphaServer that supports the bus_probe_algorithm console variable (for example, the AlphaServer 800, 1000, 1000A, 2000, 2100, or 2100A systems support the variable), you must set the bus_probe_algorithm console variable to new by entering the following command:

>>>set bus_probe_algorithm new

Use the show bus_probe_algorithm console command to determine if your system supports the variable. If the response is null or an error, there is no support for the variable. If the response is anything other than new, you must set it to new.

•On AlphaServer 1000A and 2100A systems, updating the firmware on the KZPSA-BB SCSI adapter is not supported when the adapter is behind the PCI-to-PCI bridge.

2.4.2KZPBA-CB SCSI Bus Adapter Restrictions

KZPBA-CB UltraSCSI adapters have the following restrictions:

•Each system supporting the KZPBA-CB UltraSCSI host adapter limits the number of adapters that may be installed. The maximum number of KZPBA-CB UltraSCSI host adapters supported with TruCluster Server follow:

–AlphaServer 800: 2

–AlphaServer 1000A and 1200: 4

–AlphaServer 4000: 8; only one KZPBA-CB is supported in IOD0 (PCI0).

–AlphaServer 4100: 5; only one KZPBA-CB is supported in IOD0 (PCI0).

2–6Hardware Requirements and Restrictions