Compaq AA-RHGWB-TE manual Disk Device Restrictions, RAID Array Controller Restrictions

–AlphaServer 8200, 8400, GS60, GS60E, GS140: 32

The KZPBA-CB is supported on the DWLPB only; it is not supported on the DWLPA module.

–AlphaServer DS10: 2

–AlphaServer DS20/DS20E: 4

–AlphaServer ES40: 5

•A maximum of four HSZ50, HSZ70, or HSZ80 RAID array controllers can be placed on a single KZPBA-CB UltraSCSI bus. Only two redundant pairs of array controllers are allowed on one SCSI bus.

•The KZPBA-CB requires ISP 1020/1040 firmware Version 5.57 (or higher), which is available with the system SRM console firmware on the Alpha Systems Firmware 5.3 Update CD-ROM (or later).

•The maximum length of any differential SCSI bus segment is 25 meters, including the length of the SCSI bus cables and SCSI bus internal to the SCSI adapter, hub, or storage device. A SCSI bus may have more than one SCSI bus segment (see Section 3.1).

•See the KZPBA-CB UltraSCSI Storage Adapter Module Release Notes (AA-R5XWD-TE) for more information.

2.5Disk Device Restrictions

The restrictions for disk devices are as follows:

•Disks on shared SCSI buses must be installed in external storage shelves or behind a RAID array controller.

•TruCluster Server does not support Prestoserve on any shared disk.

2.6RAID Array Controller Restrictions

RAID array controllers provide high performance, high availability, and high connectivity access to SCSI devices through a shared SCSI bus.

RAID controllers can be configured with the number of SCSI IDs as shown in Table 2–2.

Table 2–2: RAID Controller SCSI IDs

RAID Controller	Number of SCSI IDs Supported
HSZ20	4
HSZ40	4
HSZ50	4
HSZ70	8

Hardware Requirements and Restrictions 2–7