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Oracle® VM Server for SPARC 3.6 Administration Guide

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Updated: September 2019
 
 

Interactions Between the Whole-Core Constraint and Other Domain Features

CPU Dynamic Reconfiguration

The whole-core constraint is fully compatible with CPU dynamic reconfiguration (DR). When a domain is defined with the whole-core constraint, you can use the ldm add-core, ldm set-core, or ldm remove-core command to change the number of cores on an active domain.

However, if a bound or active domain is not in delayed reconfiguration mode, its number of cores cannot exceed the maximum number of cores. This maximum is set with the maximum core constraint, which is automatically enabled when the whole-core constraint is enabled. Any CPU DR operation that does not satisfy the maximum core constraint fails.

Dynamic Resource Management

The whole-core constraint is fully compatible with dynamic resource management (DRM).

    The expected interactions between the whole-core constraint and DRM are as follows:

  • While a DRM policy exists for a domain, you cannot switch the domain from being whole-core constrained to whole-core unconstrained or from being whole-core unconstrained to whole-core constrained. For example:

    • When a domain is whole-core constrained, you cannot use the ldm set-vcpu command to specify a number of virtual CPUs and to remove the whole-core constraint.

    • When a domain is not whole-core constrained, you cannot use the ldm set-core command to specify a number of whole cores and to add the whole-core constraint.

  • When a domain is whole-core constrained and you specify the attack, decay, vcpu-min, or vcpu-max value, the value must be a whole-core multiple.