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Managing shared processor pool

Managing shared processor pool

A shared processor Pool (SPP) is a pool of processor capacity that is shared between a group of virtual server instances. Unlike a virtual server instance that has a dedicated and defined maximum amount of processing capacity, you can set the reserved cores in SPP that are guaranteed to be available at the pool level.

The following table shows how an SPP is used to reduce the licensing cost when you pay per core:

Table 1. SPP helps to reduce the licensing cost
Use of SPP VM 1 VM 2 Reserved cores in Pool (User defined) License requirement per core
No Maximum cores = 5
Mode = Dedicated		 Maximum cores = 6
Mode = Dedicated		 NA 5+6 = 11
Yes Maximum cores = 5
Mode = Shared/Uncapped
Entitled capacity = 4.25		 Maximum cores = 6
Mode = Shared/Uncapped
Entitled capacity = 5.25		 Maximum cores = 10 10, Determined by reserved cores in pool

The benefits of using an SPP are as follows:

  • Provides control over licensing costs by limiting the number of processors an uncapped partition can use, which reduces the number of software licenses.
  • Provides a better overall ability to manage processor resources.

The Power Virtual Server always has at least one defined SPP as the default pool. You can add up to 63 more SPPs to a single Power Virtual Server workspace. The SPP is used and shared by a set of virtual server instances of the same machine type (host).

You can specify the host affinity and anti-affinity between two or more SPPs with shared processor pool placement groups. For more information, see Configuring shared processor pool placement group.

Pricing for shared processor pool

When you use SPP, you pay for the following items:

  • SPP reserved cores that use the shared capped part number.
  • Virtual server instance cores that are deployed into the SPP that use shared uncapped part number.

The SPP helps you to manage CPU cores only. Pricing for memory and storage remains the same as earlier. The total estimated cost page does not show the SPP reserved cores-related costs because of service-level estimator limitations. For more information about pricing, see Pricing for Power Virtual Servers.

Configuring shared processor pool

SPP is a separate resource within a Power Virtual Server workspace. You can manage the entire SPP lifecycle with the Power Virtual Server user interface.

The SPP and your Power Virtual Server workspace are linked and thus shared resource pools are not visible from different accounts. You can create one or more SPPs per workspace.

Create an SPP by specifying the following parameters:

  • A unique name
  • Host group or the machine type
  • Number of processors to reserve.

When you define these parameters, a backend process determines the best host for the new SPP.

When the SPP you create is not configured successfully on the host, the SPP will not have any allocated processing cores. You need to delete such SPPs manually as they do not get cleaned up automatically.

Creating a shared processor pool

To create an SPP, complete the following steps:

  1. Go to Shared processor pools in the Power Virtual Server user interface under Compute.

  2. Click Create pool.

  3. In the Create new shared processor pool window, define the following preferences based on your requirements:

    Table 2. Creating a new SPP fields and descriptions
    Field Description
    Name Enter a name that is unique within your cloud account.
    Use a name of minimum 2 characters and a maximum of 12 characters. Alphanumeric characters are not allowed and underscore (‘_’) is only allowed as a special character.
    Add to a pool placement group Select the checkbox if you want to deploy the SPP directly into an existing pool placement group.
    If the pool has the required affinity relation with other pools, the best practice is to deploy the pool directly into the placement group. You must create the pool placement group first. It prevents the pool from being deployed on a host that does not satisfy the affinity requirements, and having to move it later.
    Select machine type Specify the machine type. For more information about hardware specifications, see S922, and E980 (Data centers other than Dallas and Washington).
    Reserved processing cores The core-to-vCPU ratio is 1:1 by default.

  4. Click Create.

Updating or deleting a shared processor pool

To update or delete an SPP, navigate to Compute > Shared processor pools. Then select the SPP that you want to edit and click on the edit icon. You will get a notification after the SPP is deleted successfully.

You can update or delete the following details of an existing SPP:

  • Name of the SPP - Follow the same naming conventions that you used while creating an SPP. For more information, see Creating a shared processor pool.
  • Number of cores - You can update the number of reserved cores based on resource availability and allocation.
  • Delete an existing SPP - You can delete any existing SPP. Before deleting, ensure that no virtual server instances exist in the SPP. If virtual server instances are present, it must be deleted or moved with a support ticket.

Managing a virtual server instance of a shared processor pool

When you deploy a virtual server instance, you can choose an SPP instead of a host. As you cannot move a virtual server instance into or out of an SPP, you can deploy a virtual server instance directly into an SPP as a best practice. You can also deploy a virtual server instance into a server placement group; the selected SPP host must be compatible with the affinity policy of the placement group that you selected.

When you deploy multiple virtual server instances simultaneously, a new server placement group is created automatically.

During any planned maintenance activity or when you want to perform a remote restart operation, ensure that the virtual server instances are linked to an SPP based on your requirements.

Deploying a virtual server instance into a shared processor pool

To add virtual server instances to an exsiting SPP, complete the following steps:

  1. Go to Virtual server instances in the Power Virtual Server user interface under Compute.
  2. Click Create instance.
  3. Complete the input fields under the General tile based on your requirement.
  4. Select the checkbox Add to a Shared processor pool.
  5. Select an existing shared processor pool.
  6. Continue with the with the process of creating a virtual server instance. For more information, see Configuring a Power Virtual Server instance.

Configuring a shared processor pool placement group

You can configure an SPP with the shared processor pool placement group (SPP PG) to control the host in which SPPs are deployed.

SPP PGs are different from server placement groups. They serve the same purpose but cannot combine resource types.

You must define the following parameters to define an SPP PG:

  • A unique name - The SPP PG name must be unique in your cloud instance.
  • Policy - You can set the colocation policy of the SPP PG as the same server (affinity) or a different server (anti-affinity).

The following table explains how the host selection is determined based on the different options of SPP PG policy selection:

Table 3. Host selection when SPP PG is empty and non-empty
SPP PG Policy Host selection Result
Same server (Affinity) New SPP is configured on same host as determined by the existing PG SPP members. The new SPP is automatically added as a member of the PG policy.
Different server (Anti-affinity) Configure the new SPP on a different host than all host identified by all the existing PG members. The new SPP is automatically added as a member of the PG policy.
Table 3. Host selection when SPP PG is empty and non-empty
SPP PG Policy Host selection Result
Same server (Affinity) New SPP is configured on a host that is selected based on the backend processing The new SPP is automatically added as a member of the PG policy
Different server (Anti-affinity) New SPP is configured on a host that is selected based on the backend processing The new SPP is automatically added as a member of the PG policy

Creating a shared processor pool placement group

To create an SPP PG, complete the following steps:

  1. Go to Shared processor pools in the Power Virtual Server user interface under Compute.

  2. Click the Pool placement groups tab.

  3. Click Create group.

  4. In the Create new pool placement group window, enter the following details:

    Table 4. Create a new SPP PG field description
    Field Description
    Name Enter a name that is unique within your cloud account.
    Use a minimum of 2 characters and a maximum of 12 characters. Alphanumeric characters are not allowed and underscore (‘_’) is only allowed as a special character.
    Policy Same Server (Affinity)
    Different server (Anti-affinity)

  5. Click Create.

You get notified when the new SPP PG is created.

Adding a shared processor pool to a the placement group

You can add an SPP as a member, to an existing SPP PG if the host of the SPP follows the affinity policy of the group. If the PG policy is set to Same server (affinity), all SPPs that are added as a member of the placement group must remain on the same host. If the PG policy is set to Different server (anti-affinity), the SPP is deployed on a different host other than all its group members.

To add an SPP to an existing SPP PG, complete the following steps:

  1. Go to Shared processor pools in the Power Virtual Server user interface under Compute.
  2. Click the Pool placement groups tab.
  3. Select an existing pool placement group to which you want to add an SPP.
  4. Select one of the following options:
Table 5. Add SPP to an SPP PG: field description
Field Description
Add existing You can choose from existing SPPs.
Create new You can create an SPP from scratch by defining pool name, machine type, and number of cores. For more information, see Create a new SPP

You will be notified after the new SPP PG is created.

Deleting a shared processor pool placement group

To delete an SPP PG, complete the following steps:

  1. Go to Shared processor pools in the Power Virtual Server user interface under Compute.
  2. Click the Pool placement groups tab.
  3. Click the SPP PG that you want to delete.
  4. In the details page, click the delete icon.

Deleting a placement group does not delete its members or change the host in which the placement groups are deployed.