When to Use Pools

Resource pools offer a versatile mechanism that can be applied to many administrative scenarios.

Batch compute server	Use pools functionality to split a server into two pools. One pool is used for login sessions and interactive work by timesharing users. The other pool is used for jobs that are submitted through the batch system.
Application or database server	Partition the resources for interactive applications in accordance with the applications' requirements.
Turning on applications in phases	Set user expectations. You might initially deploy a machine that is running only a fraction of the services that the machine is ultimately expected to deliver. User difficulties can occur if reservation-based resource management mechanisms are not established when the machine comes online. For example, the fair share scheduler optimizes CPU utilization. The response times for a machine that is running only one application can be misleadingly fast. Users will not see these response times with multiple applications loaded. By using separate pools for each application, you can place a ceiling on the number of CPUs available to each application before you deploy all applications.
Complex timesharing server	Partition a server that supports large user populations. Server partitioning provides an isolation mechanism that leads to a more predictable per-user response. By dividing users into groups that bind to separate pools, and using the fair share scheduling (FSS) facility, you can tune CPU allocations to favor sets of users that have priority. This assignment can be based on user role, accounting chargeback, and so forth.
Workloads that change seasonally	Use resource pools to adjust to changing demand. Your site might experience predictable shifts in workload demand over long periods of time, such as monthly, quarterly, or annual cycles. If your site experiences these shifts, you can alternate between multiple pools configurations by invoking pooladm from a cron job. (See Resource Pools Framework.)
Real-time applications	Create a real-time pool by using the RT scheduler and designated processor resources.
System utilization	Enforce system goals that you establish. Use the automated pools daemon feature to identify available resources and then monitor workloads to detect when your specified objectives are no longer being satisfied. The daemon can take corrective action if possible, or the condition can be logged.

Resource Pools Framework

The /etc/pooladm.conf configuration file describes the static pools configuration. A static configuration represents the way in which an administrator would like a system to be configured with respect to resource pools functionality. An alternate file name can be specified.

When the service management facility (SMF) or the pooladm -e command is used to enable the resource pools framework, then, if an /etc/pooladm.conf file exists, the configuration contained in the file is applied to the system.

The kernel holds information about the disposition of resources within the resource pools framework. This is known as the dynamic configuration, and it represents the resource pools functionality for a particular system at a point in time. The dynamic configuration can be viewed by using the pooladm command. Note that the order in which properties are displayed for pools and resource sets can vary. Modifications to the dynamic configuration are made in the following ways:

• Indirectly, by applying a static configuration file

• Directly, by using the poolcfg command with the -d option

More than one static pools configuration file can exist, for activation at different times. You can alternate between multiple pools configurations by invoking pooladm from a cron job. See the cron(1M) man page for more information on the cron utility.

By default, the resource pools framework is not active. Resource pools must be enabled to create or modify the dynamic configuration. Static configuration files can be manipulated with the poolcfg or libpool commands even if the resource pools framework is disabled. Static configuration files cannot be created if the pools facility is not active. For more information on the configuration file, see Creating Pools Configurations.

The commands used with resource pools and the poold system daemon are described in the following man pages:

• pooladm(1M)

• poolbind(1M)

• poolcfg(1M)

• poold(1M)

• poolstat(1M)

• libpool(3LIB)

/etc/pooladm.conf Contents

All resource pool configurations, including the dynamic configuration, can contain the following elements.

system	Properties affecting the total behavior of the system
pool	A resource pool definition
pset	A processor set definition
cpu	A processor definition

All of these elements have properties that can be manipulated to alter the state and behavior of the resource pools framework. For example, the pool property pool.importance indicates the relative importance of a given pool. This property is used for possible resource dispute resolution. For more information, see libpool(3LIB).

Pools Properties

The pools facility supports named, typed properties that can be placed on a pool, resource, or component. Administrators can store additional properties on the various pool elements. A property namespace similar to the project attribute is used.

For example, the following comment indicates that a given pset is associated with a particular Datatree database.

Datatree,pset.dbname=warehouse

For additional information about property types, see poold Properties.

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Note - A number of special properties are reserved for internal use and cannot be set or removed. See the libpool(3LIB) man page for more information.

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Implementing Pools on a System

User-defined pools can be implemented on a system by using one of these methods.

• When the Solaris software boots, an init script checks to see if the /etc/pooladm.conf file exists. If this file is found and pools are enabled, then pooladm is invoked to make this configuration the active pools configuration. The system creates a dynamic configuration to reflect the organization that is requested in /etc/pooladm.conf, and the machine's resources are partitioned accordingly.

• When the Solaris system is running, a pools configuration can either be activated if it is not already present, or modified by using the pooladm command. By default, the pooladm command operates on /etc/pooladm.conf. However, you can optionally specify an alternate location and file name, and use that file to update the pools configuration.

For information about enabling and disabling resource pools, see Enabling and Disabling the Pools Facility. The pools facility cannot be disabled when there are user-defined pools or resources in use.

To configure resource pools, you must have superuser privileges or have the Process Management profile in your list of profiles. The System Administrator role includes the Process Management profile.

The poold resource controller is started with the dynamic resource pools facility.