Modern computing environments have to provide a flexible response to the varying workloads that are generated by different applications on a system. A workload is an aggregation of all processes of an application or group of applications. If resource management features are not used, the Oracle Solaris operating system responds to workload demands by adapting to new application requests dynamically. This default response generally means that all activity on the system is given equal access to resources. Resource management features enable you to treat workloads individually. You can do the following:
Restrict access to a specific resource
Offer resources to workloads on a preferential basis
Isolate workloads from each another
The ability to minimize cross-workload performance compromises, along with the facilities that monitor resource usage and utilization, is referred to as resource management. Resource management is implemented through a collection of algorithms. The algorithms handle the series of capability requests that an application presents in the course of its execution.
Resource management facilities permit you to modify the default behavior of the operating system with respect to different workloads. Behavior primarily refers to the set of decisions that are made by operating system algorithms when an application presents one or more resource requests to the system. You can use resource management facilities to do the following:
Deny resources or prefer one application over another for a larger set of allocations than otherwise permitted
Treat certain allocations collectively instead of through isolated mechanisms
The implementation of a system configuration that uses the resource management facilities can serve several purposes. You can do the following:
Prevent an application from consuming resources indiscriminately
Change an application's priority based on external events
Balance resource guarantees to a set of applications against the goal of maximizing system utilization
When planning a resource-managed configuration, key requirements include the following:
Identifying the competing workloads on the system
Distinguishing those workloads that are not in conflict from those workloads with performance requirements that compromise the primary workloads
After you identify cooperating and conflicting workloads, you can create a resource configuration that presents the least compromise to the service goals of the business, within the limitations of the system's capabilities.
Effective resource management is enabled in the Oracle Solaris system by offering control mechanisms, notification mechanisms, and monitoring mechanisms. Many of these capabilities are provided through enhancements to existing mechanisms such as the proc(4) file system, processor sets, and scheduling classes. Other capabilities are specific to resource management. These capabilities are described in subsequent chapters.