The SCSI bus listed in the hardware requirements must be configured prior to installation of Cluster Services. This includes:

•Configuring the SCSI devices.

•Configuring the SCSI controllers and hard disks to work properly on a shared SCSI bus.

•Properly terminating the bus. The shared SCSI bus must have a terminator at each end of the bus. It is possible to have multiple shared SCSI buses between the nodes of a cluster.

In addition to the information on the next page, refer to the documentation from the SCSI device manufacturer or the SCSI specifications, which can be ordered from the American National Standards Institute (ANSI). The ANSI web site contains a catalog that you can search for the SCSI specifications.

7.5.1Configuring the SCSI Devices

Each device on the shared SCSI bus must have a unique SCSI ID. Since most SCSI controllers default to SCSI ID 7, part of configuring the shared SCSI bus will be to change the SCSI ID on one controller to a different SCSI ID, such as SCSI ID 6. If there is more than one disk that will be on the shared SCSI bus, each disk must also have a unique SCSI ID.

Some SCSI controllers reset the SCSI bus when they initialize at boot time. If this occurs, the bus reset can interrupt any data transfers between the other node and disks on the shared SCSI bus. Therefore, SCSI bus resets should be disabled if possible.

7.5.2Terminating the Shared SCSI Bus

You can connect Y cables to devices if the device is at the end of the SCSI bus. You can then attach a terminator to one branch of the Y cable to terminate the SCSI bus. This method of termination requires either disabling or removing any internal terminators the device has.

Note: Any devices that are not at the end of the shared bus must have their internal termination disabled.

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Installing and Configuring Clusters

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