Groups
Groups are organizational containers used in NetMRG. They are capable of containing Devices, as well as having a View associated with them. As they are strictly organizational, the Web Interface is the only component to utilize them. They are ignored by the Gatherer.
Devices
Devices can be thought of as any physical device on your network that will be monitored. They may also be used organizationally to group Monitors that are not associated directly to any physcial host. Devices may have, but are not required to have, IP addresses, SNMP community strings, and so forth. Data gathering for Devices may be explicitly disabled. Devices contain Sub-Devices.
Sub-Devices
Sub-Devices are discrete entities on a Device. Examples of these are network interfaces, disk drives, and so forth. Sub-Devices may have parameters or variables associated with them for identification purposes. For example, a web server has a network interface designated "eth0." In NetMRG, the server would have a network interface Sub-Device which would have a variable of "ifDescr" set to "eth0." Sub-Devices contain Monitors.
Monitors
Monitors represent discrete monitorable quantities. The Gatherer performs the Monitor's Test upon the Monitor's Sub-Device. The result is then stored in a RRD. Monitors are also associated with Graph Items. If NetMRG is being used to track events, a Monitor may also contain Events.
Tests
Tests are data gathering operations associated with Monitors. There are four types of tests: Scripts, SNMP Queries, SQL Queries, and Internal tests. Script tests call a script and use either its return code or its output as data. SNMP Tests perform a SNMP GET operation against a device using a supplied OID. SQL Tests perform a MySQL query and use a value from a returned row as data. Internal tests are frequently used tests built into the Gatherer. They typically start as Script Tests but are integrated for the sake of efficiency.
Events
Events contain a group of Conditions and Responses. If the Conditions of an Event are met, the appropriate response is performed.