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5.9 Important Notes about CPU Activation


5.9 Important Notes about CPU Activation
This section provides the following notes about working with CPU Activation:
Adding/Removing CPU Cores Dynamically
You can add or remove CPU cores dynamically by using the ldm command or through automatic replacement of failed CPUs.
This is achieved through a logical dynamic reconfiguration feature with the help of Oracle VM Server for SPARC.
However, in specific configurations, instead of the dynamic reconfiguration feature being used, logical domains need to be rebooted to add/remove CPU cores.
This situation occurs when CPU cores are assigned as physical resources.
For details, see "Assigning Physical Resources to Domains" in the Oracle VM Server for SPARC Administration Guide for the version used.
Note - The SPARC M12/M10 has the following two kinds of dynamic reconfiguration (DR):
- DR function that dynamically (re-)assigns CPU core/memory resources to and from your working logical domain. This is a function provided by the Oracle VM Server for SPARC software.

- DR function that dynamically (re-)assigns a building block (which means one SPARC M12-2S or SPARC M10-4S) to and from your working physical partition. This is a function provided by the Oracle VM Server for SPARC software and the XSCF firmware.
Live Migration
The physical partition that is the migration destination of a guest domain should have enough activated CPU core resources that are not assigned to physical domains. If the number of unused activated CPU Activations is insufficient, you may need to add CPU Activations. Even for live migration between SPARC M12/M10 of the same model, CPU Activations may need to be added to the destination. This is because it is impossible to move CPU Activations between two systems (even if they are practically one system.)
For details of live migration, see "Chapter 7 Migrating a Guest Domain" in the Fujitsu SPARC M12 and Fujitsu M10/SPARC M10 Domain Configuration Guide.
Adding/Removing the SPARC M12-2S/M10-4S in a Building Block Configuration
When adding a SPARC M12-2S/M10-4S in a building block configuration, check that the number of CPU Activations is sufficient and add the unit as necessary.
Saving Logical Domain Configuration Information
If you change the configuration of a logical domain, save the logical domain information by executing the ldm add-spconfig command.
For example, suppose that you moved a logical domain to another system through live migration and reduced the number of CPU Activations on the source system. In this case, save the logical domain configuration information by using the ldm add-spconfig command after the completion of live migration.
If you do not save the configuration information of the logical domain, the domain will start with the previous configuration information the next time the physical partition is started. In this case, the number of CPU Activations may be insufficient, and thus the start may fail.
Note - Even with a system that has only the control domain in its configuration, save the logical domain configuration information when you change the resource configuration with the ldm command of Oracle VM Server for SPARC.