1 RRDTOOL(1) rrdtool RRDTOOL(1)
6 rrdtool - Round Robin Database Tool
14 It is pretty easy to gather status information from all sorts of
15 things, ranging from the temperature in your office to the number of
16 octets which have passed through the FDDI interface of your router. But
17 it is not so trivial to store this data in an efficient and systematic
18 manner. This is where R\bRR\bRD\bDt\bto\boo\bol\bl comes in handy. It lets you _\bl_\bo_\bg _\ba_\bn_\bd _\ba_\bn_\ba_\b-
20 analysis part of RRDtool is based on the ability to quickly generate
21 graphical representations of the data values collected over a definable
22 time period.
24 In this man page you will find general information on the design and
25 functionality of the Round Robin Database Tool (RRDtool). For a more
27 check the corresponding man page.
29 For an introduction to the usage of RRDtool make sure you consult the
30 rrdtutorial.
34 While the man pages talk of command line switches you have to set in
35 order to make R\bRR\bRD\bDt\bto\boo\bol\bl work it is important to note that R\bRR\bRD\bDt\bto\boo\bol\bl can be
36 remotely controlled through a set of pipes. This saves a considerable
38 quickly. Check the section on "Remote Control" further down. There is
39 also a number of language bindings for RRDtool which allow you to use
40 it directly from perl, python, tcl, php, etc.
46 u\bup\bpd\bda\bat\bte\bev\bv Operationally equivalent to u\bup\bpd\bda\bat\bte\be except for output. Check
47 rrdupdate.
50 from generating graphs, data can also be extracted to stdout.
51 Check rrdgraph.
54 restore you can use this to move an RRD from one computer
55 architecture to another. Check rrddump.
60 tion uses fetch to retrieve its data from an RRD. Check rrd-
61 fetch.
70 Change the size of individual RRAs. This is dangerous! Check
71 rrdresize.
76 Check rrdcgi.
81 Data Acquisition
82 When monitoring the state of a system, it is convenient to have
83 the data available at a constant time interval. Unfortunately,
84 you may not always be able to fetch data at exactly the time
86 any time you want. It will automatically interpolate the value
88 (intervall) and write this interpolated value to the log. The
89 original value you have supplied is stored as well and is also
90 taken into account when interpolating the next log entry.
92 Consolidation
93 You may log data at a 1 minute interval, but you might also be
94 interested to know the development of the data over the last
95 year. You could do this by simply storing the data in 1 minute
96 intervals for the whole year. While this would take consider-
97 able disk space it would also take a lot of time to analyze the
98 data when you wanted to create a graph covering the whole year.
100 solidation feature. When setting up an Round Robin Database
103 minimum, maximum, total, last) should be used to build the con-
104 solidated values (see rrdcreate). You can define any number of
108 Round Robin Archives
109 Data values of the same consolidation setup are stored into
111 store data for a certain amount of time, while using a known
112 and constant amount of storage space.
114 It works like this: If you want to store 1'000 values in 5
116 values and a header area. In the header it will store a pointer
117 telling which slots (value) in the storage area was last writ-
118 ten to. New values are written to the Round Robin Archive in,
119 you guessed it, a round robin manner. This automatically limits
120 the history to the last 1'000 values (in our example). Because
122 another one, for storing 750 data values at a 2 hour interval,
123 for example, and thus keep a log for the last two months at a
124 lower resolution.
127 and that old data is automatically eliminated. By using the
128 consolidation feature, you can still keep data for a very long
129 time, while gradually reducing the resolution of the data along
130 the time axis.
133 store exactly the type of information that actually interests
134 you: the maximum one minute traffic on the LAN, the minimum
135 temperature of your wine cellar, the total minutes of down
136 time, etc.
138 Unknown Data
140 val. Sometimes it may happen that no new data is available when
145 functions of the tool. When consolidating a data set, the
147 consolidated value is ready to be written to its Round Robin
149 the percentage of unknown values in the data point is above a
153 Graphing
156 graphing feature is fully configurable. Size, color and con-
157 tents of the graph can be defined freely. Check rrdgraph for
158 more information on this.
160 Aberrant Behavior Detection
161 by Jake Brutlag
164 rant behavior detection. These components include:
166 * An algorithm for predicting the value of a time series one
167 time step into the future.
169 * A measure of deviation between predicted and observed val-
170 ues.
172 * A mechanism to decide if and when an observed value or
174 dicted value(s).
176 Here is a brief explanation of these components:
178 The Holt-Winters time series forecasting algorithm is an on-
179 line (or incremental) algorithm that adaptively predicts future
180 observations in a time series. Its forecast is the sum of three
181 components: a baseline (or intercept), a linear trend over time
182 (or slope), and a seasonal coefficient (a periodic effect, such
183 as a daily cycle). There is one seasonal coefficient for each
184 time point in the period (cycle). After a value is observed,
185 each of these components is updated via exponential smoothing.
186 This means that the algorithm "learns" from past values and
187 uses them to predict the future. The rate of adaptation is gov-
188 erned by 3 parameters, alpha (intercept), beta (slope), and
189 gamma (seasonal). The prediction can also be viewed as a
190 smoothed value for the time series.
192 The measure of deviation is a seasonal weighted absolute devia-
194 for each time point in the seasonal cycle. As with Holt-Winters
195 forecasting, deviation is predicted using the measure computed
196 from past values (but only at that point in the seasonal
197 cycle). After the value is observed, the algorithm learns from
198 the observed value via exponential smoothing. Confidence bands
199 for the observed time series are generated by scaling the
200 sequence of predicted deviation values (we usually think of the
201 sequence as a continuous line rather than a set of discrete
202 points).
204 Aberrant behavior (a potential failure) is reported whenever
205 the number of times the observed value violates the confidence
206 bands meets or exceeds a specified threshold within a specified
207 temporal window (e.g. 5 violations during the past 45 minutes
208 with a value observed every 5 minutes).
212 data you could, for example, use a front-end application to
215 For a detailed description on how to set this up, see rrdcre-
216 ate.
221 input via standard input (STDIN). With this feature you can improve
227 rrdtool help cd|mkdir|pwd|ls|quit
229 When a command is completed, RRDtool will print the string '"OK"',
230 followed by timing information of the form u\bu:\b:_\bu_\bs_\be_\br_\bt_\bi_\bm_\be s\bs:\b:_\bs_\by_\bs_\bt_\be_\bm_\bt_\bi_\bm_\be.
231 Both values are the running totals of seconds since RRDtool was
232 started. If an error occurs, a line of the form '"ERROR:" _\bD_\be_\bs_\bc_\br_\bi_\bp_\bt_\bi_\bo_\bn
233 _\bo_\bf _\be_\br_\br_\bo_\br' will be printed instead. R\bRR\bRD\bDt\bto\boo\bol\bl will not abort, unless some-
235 0, RRDtool will do a chroot to that workdir. If the UID is not 0, RRD-
240 If you want to create a RRD-Server, you must choose a TCP/IP Service
243 rrdsrv 13900/tcp # RRD server
245 Attention: the TCP port 13900 isn't officially registered for rrdsrv.
246 You can use any unused port in your services file, but the server and
247 the client system must use the same port, of course.
249 With this configuration you can add RRDtool as meta-server to
252 rrdsrv stream tcp nowait root /opt/rrd/bin/rrdtool rrdtool - /var/rrd
254 Don't forget to create the database directory /var/rrd and reinitialize
255 your inetd.
257 If all was setup correctly, you can access the server with perl sock-
258 ets, tools like netcat, or in a quick interactive test by using 'telnet
259 localhost rrdsrv'.
262 such a port unless you are sure what you are doing.
265 rrdcreate, rrdupdate, rrdgraph, rrddump, rrdfetch, rrdtune, rrdlast,
266 rrdxport
269 Bugs? Features!
272 Tobias Oetiker <tobi@oetiker.ch>
276 1.2.28 2008-07-23 RRDTOOL(1)