RRDtool

RRDtool

Original author(s)	Tobi Oetiker
Stable release	1.4.5 / December 26, 2010
Written in	C
License	GNU General Public License
Website	http://oss.oetiker.ch/rrdtool/

RRDtool has a graph function, which presents data from an RRD in a customizable graphical format

Free software portal

RRDtool (acronym for round-robin database tool) aims to handle time-series data like network bandwidth, temperatures, CPU load, etc. The data are stored in a round-robin database (circular buffer), thus the system storage footprint remains constant over time.

It also includes tools to extract RRD data in a graphical format.

Tobi Oetiker wrote RRDtool as a solution to store and graph the time series data points of his MRTG and licenses it as free software under the terms of the GNU General Public License (GPL).

Bindings exist for Perl, Python, Ruby, Tcl, PHP and Lua. Two independent full Java implementations exist : rrd4j and jrobin.

General data storage

RRDtool assumes time-variable data in intervals of a certain length. This interval, usually named step, is specified upon creation of an RRD file and cannot be changed afterwards. Because data may not always be available at just the right time, RRDtool will automatically interpolate any submitted data to fit its internal time-steps.

The value for a specific step, that has been interpolated, is named a primary data point (PDP). Multiple PDPs may be consolidated according to a consolidation function (CF) to form a consolidated data point (CDP). Typical consolidation functions are average, minimum, maximum.

After the data have been consolidated, the resulting CDP is stored in a round-robin archive (RRA). A round-robin archive stores a fixed number of CDPs and specifies how many PDPs should be consolidated into one CDP and which CF to use. The total time covered by an RRA can be calculated as follows:

 time covered = (#CDPs stored) * (#PDPs per CDP) * steps

After this time the archive will "wrap around": the next insertion will overwrite the oldest entry. This behavior is sometimes referred to as "round-robin" and is the reason for the program's name.

To cover several timespans and/or use several consolidation functions, an RRD file may contain multiple RRAs. The data retrieval function of RRDtool automatically selects the archive with the highest resolution that still covers the requested timespan. This mechanism is also used by RRDtool's graphing subsystem.

Release history

Colour	Meaning
Red	Release no longer supported
Green	Release still supported
Blue	Future release

RRDTool is sponsored since 1.2, each release comes with a list of sponsors.

The following table contains the release history of RRDtool, showing its major releases.

Version number	Date	Links	Notable changes
1.0	July 16, 1999	Full release notes, Announce	First release. Basically MRTG "done right".
1.1	April 25, 2005	Full release notes, Announce	libart; output EPS, PDF & SVG; VDEF; trends; percentiles; updatev; Holt-Winters Forecasting; COMPUTE; .rrd format change.
1.3	June 11, 2008	Full release notes, Announce	Safer & faster file access; cairo/pango; anti-aliasing; TEXTALIGN; dashed lines; new HWPREDICT; libxml; i18n; XML dump;
1.4	October 27, 2009	Full release notes, Announce	Caching daemon; VDEF PERCENTNAN; CDEF PREDICT & PREDICTSIGMA; libDBI; graph legends positioning; Lua bindings; 3D border width; and more ...

Other tools that use RRDtool as a DBMS and/or graphing subsystem

• BackupPC
• Cacti
• Cherokee
• collectd
• Ganglia
• Iptotal
• Lighttpd
• Monitorix
• MRTG
• Munin
• Nagios
• Nmon
• ntop
• Observium
• OpenNMS
• Zenoss
• N2rrd
• ServersCheck

External links

• RRDtool homepage
• RRDtool screenshot gallery
• RRDtool tutorial

• RRD Editor