IBM Power System POWER7 Series Common Service Procedures page 153

4. The system will prevent the expansion unit from being powered off if there are failed or inactive
links in the HSL loop that the expansion unit is on, other than the links adjacent to the expansion
unit. If an attempt is made to power off the expansion unit under these circumstances, a descriptive
error message will be presented. Determine if there are failed or inactive links.
Are there external links that are not operational in the HSL loop, other than those adjacent to the
expansion unit being powered off?
No: Go to step 5.
Yes: Repair the failed or inactive links, except those adjacent to the expansion unit being powered
off. If you need assistance, contact your service provider. Then perform this procedure again.
5. Verify that the SPCN loop is complete. A 10009135 reference code in the error log indicates an
incomplete SPCN loop. A complete SPCN loop is not required, but is highly recommended.
Powering off an expansion unit with an incomplete SPCN loop could cause lost contact with other
expansion units on the SPCN loop. The expansion units that the system lost contact with will
continue to function; however, the system may log additional errors and will not be able to monitor
those units. Work with the customer to determine whether the SPCN loop is complete, whether
correction is necessary, and then continue with the next step.
6. If the system has only partitions running AIX or Linux, skip to step 10, if not go to step 7.
7. The system will prevent the expansion unit from being powered off if the expansion unit is
configured as switchable and the system that owns the HSL I/O bridge (the logical owner of the
expansion unit) is not the system that provides power to the expansion unit (the system whose
SPCN the expansion unit resides in, or SPCN system). If an attempt is made to power off the
expansion unit under these circumstances, a descriptive error message will be presented. Determine
if the expansion unit is configured as a switchable unit, either by asking the customer or referring to
Determining if an expansion unit is configured as switchable under OptiConnect.
Note: Switchable expansion units will exist only if the server makes use of Switchable Independent
Disk Pools.
Is the expansion unit configured as switchable?
No: The expansion unit is configured as private to this system. Go to step 10.
Yes: Go to step 8.
8. Determine if the logical owner of the expansion unit is the SPCN system by asking the customer or
referring to Determining if a expansion unit is configured as switchable under OptiConnect.
Is the logical owner of the expansion unit also the SPCN system?
No: Work with the customer to switch logical ownership of the HSL I/O bridge in the expansion
unit to the SPCN system. This should be done by using the OptiConnect user interface, a feature
of IBM i. If that is not successful due to problems with the OptiConnect user interface, it may be
attempted as described in . Switching ownership of an expansion units switchable resources.
However, this should be used only as a last resort since it may result in Cluster Resource Group
(CRG) problems. If the switch cannot be performed, contact your service provider for assistance.
Otherwise, continue with step 9 from the SPCN system.
Yes: Go to step 9.
9. The system will prevent the expansion unit from being powered off if it contains resources included
in an active Cluster Resource Group (CRG). If an attempt is made to power off the expansion unit
under these circumstances, a descriptive error message will be presented. Determine if the expansion
unit contains resources included in an active CRG by asking the customer.
Does the expansion unit contain resources included in an active CRG?
No: Go to step 10.
Yes: Work with the customer to end each active CRG that contains resources in the expansion
unit.
10. Determine if any of the I/O resources in the expansion unit are owned by partitions running Linux.
Are any of the I/O resources in the expansion unit owned by partitions running Linux?
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