Understanding Resource Management in the Solaris OS
The main concept behind resource management is that workloads on a server need
to be balanced for the system to work efficiently. Without good resource management,
faulty runaway workloads can bring progress to a halt, causing unnecessary delays to
priority jobs. An additional benefit is that efficient resource management enables organizations to
economize by consolidating servers. To enable the management of resources, the Solaris OS
provides a structure for organizing workloads and resources, and provides controls for defining the
quantity of resources that a particular unit of workload can consume. For an
in-depth discussion of resource management from the system administrator's viewpoint, see Chapter 1, Introduction to Solaris Resource Manager, in System Administration Guide: Solaris Containers-Resource Management and Solaris Zones.
Workload Organization
The basic unit of workload is the process. Process IDs (PIDs) are numbered
sequentially throughout the system. By default, each user is assigned by the system
administrator to a project, which is a network–wide administrative identifier. Each successful login to
a project creates a new task, which is a grouping mechanism for processes.
A task contains the login process as well as subsequent child processes.
For more information on projects and tasks, see Chapter 2, Projects and Tasks (Overview), in System Administration Guide: Solaris Containers-Resource Management and Solaris Zones for the system administrator's
perspective or Chapter 2, Projects and Tasks for the developer's point of view.
Processes can optionally be grouped into non-global zones, which are set up by system
administrators for security purposes and to isolate processes. A zone can be thought
of as a box in which one or more applications run isolated from
all other applications on the system. Non-global zones are discussed thoroughly in Part II, Zones, in System Administration Guide: Solaris Containers-Resource Management and Solaris Zones. To
learn more about special precautions for writing resource management applications that run in
zones, see Chapter 7, Design Considerations for Resource Management Applications in Solaris Zones
Resource Organization
The system administrator can assign workloads to specific CPUs or defined groups of
CPUs in the system. CPUs can be grouped into processor sets, otherwise known
as psets. A pset in turn can be coupled with one or more
thread scheduling classes, which define CPU priorities, into a resource pool. Resource pools provide a
convenient mechanism for a system administrator to make system resources available to users.
Chapter 12, Resource Pools (Overview), in System Administration Guide: Solaris Containers-Resource Management and Solaris Zones covers resource pools for system administrators. Programming considerations are described in Chapter 6, Resource Pools.
The following diagram illustrates how workload and computer resources are organized in the
Solaris OS.
Figure 1-1 Workload and Resource Organization in the Solaris Operating System
Resource Controls
Simply assigning a workload unit to a resource unit is insufficient for managing
the quantity of resources that users consume. To manage resources, the Solaris OS
provides a set of flags, actions, and signals that are referred to collectively
as resource controls. Resource controls are stored in the /etc/project file or in a
zone's configuration through the zonecfg command described in zonecfg(1M). The Fair Share Scheduler (FSS),
for example, can allocate shares of CPU resources among workloads based on the
specified importance factor for the workloads. With these resource controls, a system administrator
can set privilege levels and limit definitions for a specific zone, project, task,
or process. To learn how a system administrator uses resource controls, see Chapter 6, Resource Controls (Overview), in System Administration Guide: Solaris Containers-Resource Management and Solaris Zones.
For programming considerations, see Chapter 5, Resource Controls.
Extended Accounting Facility
In addition to the workload and resource organization, the Solaris OS provides the
extended accounting facility for monitoring and recording system resource usage. The extended accounting facility provides system
administrators with a detailed set of resource consumption statistics on processes and tasks.
The facility is described in depth for system administrators in Chapter 4, Extended Accounting (Overview), in System Administration Guide: Solaris Containers-Resource Management and Solaris Zones. The Solaris
OS provides developers with both a C interface and a Perl interface to
the extended accounting facility. Refer to Chapter 3, Using the C Interface to Extended Accounting for the C interface or
Chapter 4, Using the Perl Interface to Extended Accounting for the Perl interface.
