Chapter 12

Resource Pools (Overview)

This chapter discusses the following features:

• Resource pools, which are used for partitioning machine resources

• Dynamic resource pools (DRPs), which dynamically adjust each resource pool's resource allocation to meet established system goals

Resource pools and dynamic resource pools are services in the Solaris service management facility (SMF). Each of these services is enabled separately.

The following topics are covered in this chapter:

• Introduction to Resource Pools

• Introduction to Dynamic Resource Pools

• About Enabling and Disabling Resource Pools and Dynamic Resource Pools

• Resource Pools Used in Zones

• When to Use Pools

• Resource Pools Framework

• Implementing Pools on a System

• project.pool Attribute

• SPARC: Dynamic Reconfiguration Operations and Resource Pools

• Creating Pools Configurations

• Directly Manipulating the Dynamic Configuration

• poold Overview

• Managing Dynamic Resource Pools

• Configuration Constraints and Objectives

• poold Features That Can Be Configured

• How Dynamic Resource Allocation Works

• Using poolstat to Monitor the Pools Facility and Resource Utilization

• Commands Used With the Resource Pools Facility

For procedures using this functionality, see Chapter 13, Creating and Administering Resource Pools (Tasks).

Introduction to Resource Pools

Resource pools enable you to separate workloads so that workload consumption of certain resources does not overlap. This resource reservation helps to achieve predictable performance on systems with mixed workloads.

Resource pools provide a persistent configuration mechanism for processor set (pset) configuration and, optionally, scheduling class assignment.

Figure 12-1 Resource Pool Framework

A pool can be thought of as a specific binding of the various resource sets that are available on your system. You can create pools that represent different kinds of possible resource combinations:

pool1: pset_default

pool2: pset1

pool3: pset1, pool.scheduler="FSS"

By grouping multiple partitions, pools provide a handle to associate with labeled workloads. Each project entry in the /etc/project file can have a single pool associated with that entry, which is specified using the project.pool attribute.

When pools are enabled, a default pool and a default processor set form the base configuration. Additional user-defined pools and processor sets can be created and added to the configuration. A CPU can only belong to one processor set. User-defined pools and processor sets can be destroyed. The default pool and the default processor set cannot be destroyed.

The default pool has the pool.default property set to true. The default processor set has the pset.default property set to true. Thus, both the default pool and the default processor set can be identified even if their names have been changed.

The user-defined pools mechanism is primarily for use on large machines of more than four CPUs. However, small machines can still benefit from this functionality. On small machines, you can create pools that share noncritical resource partitions. The pools are separated only on the basis of critical resources.

Introduction to Dynamic Resource Pools

Dynamic resource pools provide a mechanism for dynamically adjusting each pool's resource allocation in response to system events and application load changes. DRPs simplify and reduce the number of decisions required from an administrator. Adjustments are automatically made to preserve the system performance goals specified by an administrator. The changes made to the configuration are logged. These features are primarily enacted through the resource controller poold, a system daemon that should always be active when dynamic resource allocation is required. Periodically, poold examines the load on the system and determines whether intervention is required to enable the system to maintain optimal performance with respect to resource consumption. The poold configuration is held in the libpool configuration. For more information on poold, see the poold(1M) man page.

About Enabling and Disabling Resource Pools and Dynamic Resource Pools

To enable and disable resource pools and dynamic resource pools, see Enabling and Disabling the Pools Facility.

Resource Pools Used in Zones

On a system that has zones enabled, a non-global zone can be associated with one resource pool, although the pool need not be exclusively assigned to a particular zone. Moreover, you cannot bind individual processes in non-global zones to a different pool by using the poolbind command from the global zone. To associate a non-global zone with a pool, see Configuring, Verifying, and Committing a Zone.

Note that if you set a scheduling class for a pool and you associate a non-global zone with that pool, the zone uses that scheduling class by default.

If you are using dynamic resource pools, the scope of an executing instance of poold is limited to the global zone.

The poolstat utility run in a non-global zone displays only information about the pool associated with the zone. The pooladm command run without arguments in a non-global zone displays only information about the pool associated with the zone.

For information about resource pool commands, see Commands Used With the Resource Pools Facility.