High Availability or Multiple SCSI System Checks

If you have a high-availability configuration, or if more than one system is attached to the same SCSI bus, do the following:

  1. Verify that the adapters and devices have unique SCSI addresses. The default SCSI adapter address is always 7. If you have more than one adapter on the bus, change the address of at least one adapter. This can be done by using SMIT (SMIT Devices -> SCSI Adapter -> Change/Show characteristics of an adapter). You must make the changes to the database only, then reboot the system in order for the change to take effect.
    Note:
    Diagnostics defaults to using ID 7 (it is recommended that this ID not be used in high availability configurations).
  2. If RAID devices such as the 7135 or 7137 are attached, be sure to run the proper diagnostics for the device. If problems occur, contact your service support structure for assistance. If the diagnostics are run incorrectly on these devices, misleading SRNs can result.
  3. Diagnostics cannot be run against OEM devices; doing so results in misleading SRNs.
  4. Verify that all cables are connected securely and that both ends of the SCSI bus is terminated correctly.
  5. Verify that the cabling configuration does not exceed the maximum cable length for the adapter in use. Refer to the SCSI Cabling section in the RS/6000(R) eServer(TM) pSeries(R) Adapters, Devices, and Cable Information for Multiple Bus Systems for more details on SCSI cabling issues.
  6. Verify that adapter and devices are at the appropriate microcode levels for the customer situation. If you need assistance with microcode issues, contact your service support structure.