NFR Glossary
- alert
- A message that generally indicates some unusual condition about which the user
should be aware. Alerts can come from a program that has encountered a problem, from N
code designed to send alerts, or from a backend that has noticed something interesting
about the data it is recording.
- alertd
- The maintenance process that is responsible for managing alerts generated by the NFR
software during execution.
- backend
- A set of information that specifies an information processor. A backend is usually a
combination of a recorder process, a query process, a schema, and options specific to that
individual backend.
- engine
- The central process that decides where packet data flows through out the system.
Also referred to as nfrd.
- expire
- The term used within the Space Management subsystem when an archived file needs to be
removed from the system. Archived data can be expired because the size of an individual
archive exceeds a configured amount of disk space or the data is older than a site
configured time limit.
- filter
- A piece of N code that runs in response to some event, usually data arriving from the
network. The filter typically identifies interesting data and sends it to a recorder.
- graphical user interface
- The program that allows you to configure various settings, query backends, and
view alerts.
- histogram recorder
- One of the default recorders provided with NFR. The histogram recorder adds a new
row to the list of information if the information is all new. If any of the
information already exists in the list, the histogram recorder increases the count in the
cell to provide
- list recorder
- One of the default recorders provided with NFR. The list recorder keeps a
list of data that it has recieved. Each record sent to it is added as a new row at the end
of the list.
- maintenance process
- A program within NFR that helps keep the system running smoothly. These processes
include the nfrwatch and the space manager.
- N code
- The programming language used to write rules for the NFR engine.
- nfrd
- The central process that decides where packet data flows through out the system.
- nfrwatch
- The maintenance process that starts the components of NFR and, if needed, restarts them
while the system is running.
- package
- A group of backends. Backends are grouped in packages for convenience (keeping related
things together) or because they share N code.
- query process
- A process that runs in response to queries submitted from the GUI.
- queue process
- A program that manages a list of information and sends the information to the correct
program for further action.
- recorder
- A process that receives data from the engine and processes it further. What the
recorder does with the data depends on the type of the recorder. NFR includes two
recorders: the histogram recorder and the list recorder, both of which write the
information to a log file.
- rollover
- An option for specifying when to stop using one file and begin using another file.
- schema
- A data description of the information that the engine passes to the recorder.
- spacemand
- The maintenance process responsible for managing the space that the archived data takes
up on disk. It provides for processing and expiration of data that exceeds the configured
database size and age limits.
- stealth mode
- The operational state in which NFR does not acknowledge its existence on the network.
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