IBM SG24-5131-00 manual Scsi Adapters, RAID Enclosures, Connecting RAID Subsystems

Models: SG24-5131-00

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3.3.2.1 Cabling

The following sections describe important information about cabling.

SCSI Adapters

A overview of SCSI adapters that can be used on a shared SCSI bus is given in 2.3.2.3, “Supported SCSI Adapters” on page 26. For the necessary adapter changes, see 3.3.2.3, “Adapter SCSI ID and Termination change” on page 77.

RAID Enclosures

The 7135 RAIDiant Array can hold a maximum of 30 single-ended disks in two units (one base and one expansion). It has one controller by default, and another controller can be added for improved performance and availability. Each controller takes up one SCSI ID. The disks sit on internal single-ended buses and hence do not take up IDs on the external bus. In an HACMP cluster, each 7135 should have two controllers, each of which is connected to a separate shared SCSI bus. This configuration protects you against any failure (SCSI adapter, cables, or RAID controller) on either SCSI bus.

Because of cable length restrictions, a maximum of two 7135s on a shared SCSI bus are supported by HACMP.

3.3.2.2 Connecting RAID Subsystems

In this section, we will list the different components required to connect RAID subsystems on a shared bus. We will also show you how to connect these components together.

The 7135-110 RAIDiant Array can be connected to multiple systems on either an 8-bit or a 16-bit SCSI-2 differential bus. The Model 210 can only be connected to a 16-bit SCSI-2 Fast/Wide differential bus, using the Enhanced SCSI-2 Differential Fast/Wide Adapter/A.

To connect a set of 7135-110s to SCSI-2 Differential Controllers on a shared

8-bit SCSI bus, you need the following:

SCSI-2 Differential Y-Cable

FC: 2422 (0.765m), PN: 52G7348

SCSI-2 Differential System-to-System Cable

FC: 2423 (2.5m), PN: 52G7349

This cable is used only if there are more than two nodes attached to the same shared bus.

• Differential SCSI Cable (RAID Cable)

FC: 2901 or 9201 (0.6m), PN: 67G1259 - OR -

Cluster Hardware and Software Preparation

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IBM SG24-5131-00 manual Scsi Adapters, RAID Enclosures, Connecting RAID Subsystems