26 IBM Certification Study Guide AIX HACMP
2.3.2 SCSI Disks
After the announcement of the 7133 SSA Disk Subsystems, the SCSI Disk
subsystems became less common in HACMP clusters. However, the 7135
RAIDiant Array (Model 110 and 210) and other SCSI Subsystems are still in
use at many customer sites. We will not describe other SCSI Subsystems
such as 9334 External SCSI Disk Storage. See the appropriate
documentation if you need information about these SCSI Subsystems.
The 7135 RAIDiant Array is offered with a range of features, with a maximum
capacity of 135 GB (RAID 0) or 108 GB (RAID-5) in a single unit, and uses
the 4.5 GB disk drive modules. The array enclosure can be integrated into a
RISC System/6000 system rack, or into a deskside mini-rack. It can attach to
multiple systems through a SCSI-2 Differential 8-bit or 16-bit bus.
2.3.2.1 Capacities

Disks

There are four disk sizes available for the 7135 RAIDiant Array Models 110
and 210:
• 1.3 GB
• 2.0 GB
• 2.2 GB (only supported by Dual Active Software)
• 4.5 GB (only supported by Dual Active Software)
Subsystems
The 7135-110/210 can contain 15 Disks (max. 67.5 GB) in the base
configuration and 30 Disks (max. 135 GB) in an extended configuration.You
can for example only use the full 135 GB storage space for data if you
configure the 7135 with RAID level 0. When using RAID level 5, only 108 GB
of the 135 GB are available for data storage.
2.3.2.2 How Many in a String?
HACMP supports a maximum of two 7135s on a shared SCSI bus. This is
because of cable length restrictions.
2.3.2.3 Supported SCSI Adapters
The SCSI adapters that can be used to connect RAID subsystems on a
shared SCSI bus in an HACMP cluster are:
• SCSI-2 Differential Controller (MCA, FC: 2420, Adapter Label: 4-2)
• SCSI-2 Differential Fast/Wide Adapter/A (MCA, FC: 2416, Adapter Label:
4-6)