Chapter 2: Control Data Collection › Data Collection

Data Collection

Running as a detached process, a Performance Agent collects a variety of system and process data. The software uses both sampling and event-driven techniques in collecting data.

More than one Performance Agent can be running and collecting data on a system. The primary Performance Agent must be running before you start any alternate Performance Agents. Sampling the data produced by the primary Performance Agent, alternate Performance Agents act as clients.

When the Performance Agent software is installed a schedule file is created which contains parameters governing the primary Performance Agent. These parameters comprise the collection definition named CPD. Use the ADVISE COLLECT SHOW ALL command to display the schedule file. For an example display, see Examining the Schedule File in this chapter.

The use of alternate Performance Agents enables you to select the classes of data you want to collect and the interval at which you want to collect the data. You customize data collection by creating or modifying a collection definition in the schedule file. A collection definition, its associated parameters, and data are identified by the name you give to the definition.

You can create alternate collectors using the ADVISE COLLECT ADD command or the DECwindows interface. The collection definitions you create will then appear in the schedule file. For examples of a schedule file, see Examining the Schedule File in this chapter.

A Real-time Performance Agent is a special Performance Agent for dynamic viewing. There are two kinds of Real-time Performance Agents. One type of Real-time Performance Agent is started on a remote or local node using DECnet. The other type accesses the data currently being recorded to a disk file either by the primary Performance Agent or by a specified alternate Performance Agent. If the data is currently being recorded, you can view this data in real time, but you must have the SYSLCK privilege. See the chapters covering Real-time displays in the Performance Manager Administrator Guide and the SDK Guide.