Compaq TruCluster Server AA-RHGWB-TE, Manual

Page: 47 / 320

– 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.
2.5 Disk 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.
2.6 RAID 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