Configuring the System With Hard Partitions

This section describes hard partitioning with the Oracle VM Server for SPARC software, and how to use hard partitioning to conform to the Oracle CPU licensing requirements.

• CPU cores and CPU threads. The Oracle VM Server for SPARC software runs on Oracle's SPARC T-Series servers that use SPARC T-Series processors. SPARC T-Series processors have multiple CPU cores, each of which contains multiple CPU threads.

• Hard partitioning and CPU whole cores. Beginning with the Oracle VM Server for SPARC 2.0 release, hard partitioning is enforced by using CPU whole-core configurations. A CPU whole-core configuration has domains that are allocated CPU whole cores instead of individual CPU threads. By default, a domain is configured to use CPU threads.

  When binding a domain in a whole-core configuration, the system provisions the specified number of CPU cores and all its CPU threads to the domain. Using a CPU whole-core configuration limits the number of CPU cores that can be dynamically assigned to a bound or active domain.

• Oracle hard partition licensing. To conform to the Oracle hard partition licensing requirement, you must use at least the Oracle VM Server for SPARC 2.0 release. You must also use CPU whole cores as follows:

  • If a domain runs applications that use Oracle hard partition licensing, that domain must be configured with CPU whole cores.

  • If a domain does not run applications that use Oracle hard partition licensing, that domain is not required to be configured with CPU whole cores. For example, if you do not run any Oracle applications in the control domain, that domain is not required to be configured with CPU whole cores.

Checking the Configuration of a Domain

The tasks in this section explain how to determine whether a domain is configured with CPU whole cores and how to list the CPU cores that are assigned to a domain.

How to Determine Whether a Domain Is Configured With CPU Whole Cores

• Determine whether the domain is configured with CPU whole cores.

  # ldm list -o resmgmt domain

  Verify that the whole-core constraint appears in the output and that the max-cores property specifies the maximum number of CPU cores that are configured for the domain. See the ldm(1M) man page.

Example 10-2 Determining Whether a Domain Is Configured With CPU Whole Cores

The following command shows that the ldg1 domain is configured with CPU whole cores and a maximum of five cores:

# ldm list -o resmgmt ldg1
NAME
ldg1

CONSTRAINT
   whole-core
   max-cores=5

How to List the CPU Cores That Are Assigned to a Domain

When a domain is bound, CPU cores are assigned to the domain.

• List the CPU cores that are assigned to a domain.

  # ldm list -o core domain

Example 10-3 Listing the CPU Cores That Are Assigned to a Domain

The following command shows the cores that are assigned to the ldg1 domain:

# ldm list -o core ldg1
NAME 
ldg1

CORE 
CID    PCPUSET 
1    (8, 9, 10, 11, 12, 13, 14, 15) 
2    (16, 17, 18, 19, 20, 21, 22, 23)

Configuring a Domain With CPU Whole Cores

The tasks in this section explain how to create a new domain with CPU whole cores, how to configure an existing domain with CPU whole cores, and how to configure the primary domain with CPU whole cores.

Use the following command to configure a domain to use CPU whole cores:

ldm set-core number-of-cpu-cores domain

This command also specifies the maximum number of CPU cores for the domain, which is the CPU cap. See the ldm(1M) man page.

Starting with the Oracle VM Server for SPARC 2.2 release, the CPU cap and the allocation of CPU cores is handled by separate commands. By using these commands, you can independently allocate CPU cores, set a cap, or both. The allocation unit can be set to cores even when no CPU cap is in place. However, running the system in this mode is not acceptable for configuring hard partitioning on your Oracle VM Server for SPARC system.

• Allocate the specified number of CPU cores to a domain by using the add-core, set-core, or rm-core subcommand.

• Set the CPU cap by using the create-domain or set-domain subcommand to specify the max-cores property value.

  You must set the cap if you want to configure hard partitioning on your Oracle VM Server for SPARC system.

How to Create a New Domain With CPU Whole Cores

1. Create the domain.

   # ldm create domain

2. Set the number of CPU whole cores for the domain.

   # ldm set-core number-of-cpu-cores domain

   This command also sets the maximum number of CPU cores for the domain to number-of-cpu-cores.

3. Configure the domain.

   During this configuration, ensure that you use the ldm add-core, ldm set-core, or ldm rm-core command.

4. Bind and start the domain.

   # ldm bind domain
   # ldm start domain

Example 10-4 Creating a New Domain With Two CPU Whole Cores

This example creates a domain, ldg1, with two CPU whole cores. The first command creates the ldg1 domain. The second command configures the ldg1 domain with two CPU whole cores. The second command also sets the maximum number of CPU cores for ldg1 to two.

At this point, you can perform further configuration on the domain, subject to the restrictions described in Step 3 in How to Create a New Domain With CPU Whole Cores.

The third and fourth commands show how to bind and start the ldg1 domain, at which time you can use the ldg1 domain.

# ldm create ldg1
# ldm set-core 2 ldg1
...
# ldm bind ldg1
# ldm start ldg1

How to Configure an Existing Domain With CPU Whole Cores

If a domain already exists and is configured to use CPU threads, you can change its configuration to use CPU whole cores.

1. Stop and unbind the domain.

   # ldm stop domain
   # ldm unbind domain

2. Set the number of CPU whole cores for the domain.

   # ldm set-core number-of-cpu-cores domain

   This command also sets the maximum number of CPU cores for the domain to number-of-cpu-cores.

3. Rebind and restart the domain.

   # ldm bind domain
   # ldm start domain

Example 10-5 Configuring an Existing Domain With Four CPU Whole Cores

This example updates the configuration of an existing domain, ldg1. The first and second commands stop and unbind the ldg1 domain. The third command configures the ldg1 domain with four CPU whole cores. This command also sets the maximum number of CPU cores for ldg1 to four. The fourth and fifth commands bind and restart the ldg1 domain.

# ldm stop ldg1
# ldm unbind ldg1
# ldm set-core 4 ldg1
# ldm bind ldg1
# ldm start ldg1

How to Configure the Primary Domain With CPU Whole Cores

If the primary domain is configured to use CPU threads, you can change its configuration to use CPU whole cores.

1. Place the primary domain in delayed reconfiguration mode.

   # ldm start-reconf primary

2. Set the number of CPU whole cores for the primary domain.

   # ldm set-core number-of-cpu-cores primary

   This command also sets the maximum number of CPU cores for the primary domain to number-of-cpu-cores.

3. Reboot the primary domain.

   Use the appropriate procedure to reboot the primary domain, which depends on the system configuration. See Rebooting the primary Domain.

Example 10-6 Configuring the primary Domain With Two CPU Whole Cores

This example configures CPU whole cores on the primary domain. The first command initiates delayed reconfiguration mode on the primary domain. The second command configures the primary domain with two CPU whole cores. This command also sets the maximum number of CPU cores for the primary domain to two. The third command reboots the primary domain.

# ldm start-reconf primary
# ldm set-core 2 primary
# shutdown -i 5

Interaction With Other Oracle VM Server for SPARC Features

CPU Dynamic Reconfiguration

You can use CPU dynamic reconfiguration with domains that are configured with CPU whole cores. However, you can only add or remove entire CPU cores, not individual CPU threads. Thus, the hard partitioning state of the system is maintained by the CPU dynamic reconfiguration feature. In addition, if CPU cores are dynamically added to a domain, the maximum is enforced. Thus, the CPU DR command would fail if it attempted to exceed the maximum number of CPUs.

Use the following commands to dynamically add, set, or remove CPU whole cores to a bound or active domain:

ldm add-core number-of-cpu-cores domain
ldm set-core number-of-cpu-cores domain
ldm rm-core number-of-cpu-cores domain

Example 10-7 Dynamically Adding Two CPU Whole Cores to a Domain

This example shows how two CPU whole cores are dynamically added to the ldg1 domain. The ldg1 domain is an active domain that has been configured with CPU whole cores. The first command shows that the ldg1 domain is active. The second command shows that the ldg1 domain is configured with CPU whole cores and a maximum of four CPU cores. The third and fifth commands show the CPU cores that are assigned to the domain before and after the addition of two CPU whole cores. The fourth command dynamically adds two CPU whole cores to the ldg1 domain.

# ldm list ldg1
NAME    STATE   FLAGS   CONS  VCPU  MEMORY UTIL  UPTIME
ldg1    active  -n----  5000  16    2G     0.4%  5d 17h 49m
# ldm list -o resmgmt ldg1
NAME
ldg1

CONSTRAINT
   whole-core
        max-cores=4
# ldm list -o core ldg1
NAME 
ldg1

CORE 
CID    PCPUSET 
1    (8, 9, 10, 11, 12, 13, 14, 15) 
2    (16, 17, 18, 19, 20, 21, 22, 23)
# ldm add-core 2 ldg1
# ldm list -o core ldg1
NAME 
ldg1

CORE 
CID    PCPUSET 
1    (8, 9, 10, 11, 12, 13, 14, 15) 
2    (16, 17, 18, 19, 20, 21, 22, 23) 
3    (24, 25, 26, 27, 28, 29, 30, 31)
4    (32, 33, 34, 35, 36, 37, 38, 39)

CPU Dynamic Resource Management

Dynamic resource management (DRM) can be used to automatically manage CPU resources on some domains. If DRM is used, the DRM policies do not apply to those domains that are configured with CPU whole cores.

A DRM policy can include a domain that is configured with CPU whole cores. However, when such a policy is activated, it is automatically disabled for that domain. The domain remains configured with CPU whole cores, unless and until the domain is later reconfigured with CPU threads instead of CPU whole cores. When the domain is configured to use CPU threads, the DRM policy is automatically re-enabled for that domain.

CPU Power Management

You can use CPU power management (PM) with the performance or elastic policies enabled for domains that are configured with CPU whole cores. Using PM maintains the hard partitioning of the system.

Domain Reboot or Rebind

A domain that is configured with CPU whole cores remains configured with CPU whole cores when the domain is restarted, or if the entire system is restarted. A domain uses the same physical CPU cores for the entire time it remains bound. For example, if a domain is rebooted, it uses the same physical CPU cores both before and after the reboot. Or, if the entire system is powered off while a domain is bound, that domain will be configured with the same physical CPU cores when the system is powered on again. If you unbind a domain and then rebind it, or if the entire system is restarted with a new configuration, the domain might use different physical CPU cores.

Domain Migration Incompatibility

A CPU whole-core configuration is incompatible with a domain migration. However, you can still migrate a domain that is configured with CPU whole cores. After such a migration, hard partitioning is not enforced on the target system. Also, the whole-core configuration and the maximum number of CPU cores are not preserved by the migration on the target system.

If you migrate a domain that is configured with whole cores, you must reconfigure the target domain to use hard partitioning after the migration completes. Also, you must ensure that your license agreement permits you to use the domain on both the source and the target systems.