Choosing a Policy Type

How do you decide which policy type to use? Table 2-1 answers this question for several common use cases. The section following the table helps you decide between using an OwnBorrow policy or a utilization policy.

Table 2-1 Choosing a Policy Type

If...	Use the following type of policy...
You want gWLM to allocate a constant amount of CPU resources to a workload.	Fixed
You have your own metric by which you want gWLM to manage a workload.	Custom
IT acts as a service provider to business units.	OwnBorrow This policy type allows you to set an owned amount of resources, while also giving you control over how workloads borrow and lend resources. gWLM provides a “topborrowers” report and a “resourceaudit” report to help you manage your data center using this model. For more information, see gwlmreport(1M).
You have static vpars, but you want to move to a model where cores migrate among vpars.	OwnBorrow For each vpar, set its number of owned cores to its static number of cores. The vpar gets those owned cores whenever needed.
You have npars but, you want to move to a model where CPU resources migrate among npars.	OwnBorrow Install the HP Instant Capacity product on each npar. (This software allows gWLM to simulate CPU resource movement among npars with spare capacity.) For each npar, set its number of owned cores to the number of cores you want the npar to have whenever needed.
You want to tap into a pool of resources taking or giving CPU resources as needed—with possibly no access to resources beyond a minimum request.	Utilization
You have a policy that should be in effect only for a given time period, for the duration of a file's existence, or for a certain Serviceguard condition.	Conditional Select an existing policy and a default policy and then set a time-based condition, set a file-based condition, or choose from the possible Serviceguard conditions.

Choosing Between an OwnBorrow Policy and a Utilization Policy

OwnBorrow and utilization policies both allocate resources to a workload based on the workload's use of its current allocation. Both policy types also specify minimum and maximum amounts of resources the workload should get. A workload with either type of policy can lend other workloads its unused resources—down to its minimum. (If the workload does not consume its entire minimum allocation, those unused resources are not available to other workloads.) OwnBorrow policies, however, provide greater control in lending resources because they also have an owned amount of resources. A workload always gets its owned resources back whenever needed. So, with an OwnBorrow policy, you can set a lower minimum allocation (increasing the amount of resources available for sharing among workloads), knowing the associated workloads get their owned resources whenever needed. Thus, an OwnBorrow policy provides greater flexibility in attempting to allocate a workload a certain amount of resources when needed while also lending those resources to other workloads when not needed.

Combining the Different Policy Types

Each workload in an SRD must have a policy. Starting with gWLM A.02.00.00.07, you can use any combination of the policy types within an SRD.

Choosing a Policy Type

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Choosing Between an OwnBorrow Policy and a Utilization Policy

Combining the Different Policy Types