1RRDCREATE(1)                        rrdtool                       RRDCREATE(1)
2
3
4

NAME

6       rrdcreate - Set up a new Round Robin Database
7

SYNOPSIS

9       rrdtool create filename [--start|-b start time] [--step|-s step]
10       [--template|-t template-file] [--source|-r source-file]
11       [--no-overwrite|-O] [--daemon|-d address] [DS:ds-name[=mapped-ds-
12       name[[source-index]]]:DST:dst arguments] [RRA:CF:cf arguments]
13

DESCRIPTION

15       The create function of RRDtool lets you set up new Round Robin Database
16       (RRD) files.  The file is created at its final, full size and filled
17       with *UNKNOWN* data, unless one or more source RRD files have been
18       specified and they hold suitable data to "pre-fill" the new RRD file.
19
20   filename
21       The name of the RRD you want to create. RRD files should end with the
22       extension .rrd. However, RRDtool will accept any filename.
23
24   --start|-b start time (default: now - 10s)
25       Specifies the time in seconds since 1970-01-01 UTC when the first value
26       should be added to the RRD. RRDtool will not accept any data timed
27       before or at the time specified.
28
29       See also "AT-STYLE TIME SPECIFICATION" in rrdfetch for other ways to
30       specify time.
31
32       If one or more source files is used to pre-fill the new RRD, the
33       --start option may be omitted. In that case, the latest update time
34       among all source files will be used as the last update time of the new
35       RRD file, effectively setting the start time.
36
37   --step|-s step (default: 300 seconds)
38       Specifies the base interval in seconds with which data will be fed into
39       the RRD.  A scaling factor may be present as a suffix to the integer;
40       see "STEP, HEARTBEAT, and Rows As Durations".
41
42   --no-overwrite|-O
43       Do not clobber an existing file of the same name.
44
45   --daemon|-d address
46       Address of the rrdcached daemon.  For a list of accepted formats, see
47       the -l option in the rrdcached manual.
48
49        rrdtool create --daemon unix:/var/run/rrdcached.sock /var/lib/rrd/foo.rrd I<other options>
50
51   [--template|-t template-file]
52       Specifies a template RRD file to take step, DS and RRA definitions
53       from. This allows one to base the structure of a new file on some
54       existing file. The data of the template file is NOT used for pre-
55       filling, but it is possible to specify the same file as a source file
56       (see below).
57
58       Additional DS and RRA definitions are permitted, and will be added to
59       those taken from the template.
60
61   --source|-r source-file
62       One or more source RRD files may be named on the command line. Data
63       from these source files will be used to prefill the created RRD file.
64       The output file and one source file may refer to the same file name.
65       This will effectively replace the source file with the new RRD file.
66       While there is the danger to loose the source file because it gets
67       replaced, there is no danger that the source and the new file may be
68       "garbled" together at any point in time, because the new file will
69       always be created as a temporary file first and will only be moved to
70       its final destination once it has been written in its entirety.
71
72       Prefilling is done by matching up DS names, RRAs and consolidation
73       functions and choosing the best available data resolution when doing
74       so. Prefilling may not be mathematically correct in all cases (e.g. if
75       resolutions have to change due to changed stepping of the target RRD
76       and old and new resolutions do not match up with old/new bin boundaries
77       in RRAs).
78
79       In other words: A best effort is made to preserve data during
80       prefilling.  Also, pre-filling of RRAs may only be possible for certain
81       kinds of DS types. Prefilling may also have strange effects on Holt-
82       Winters forecasting RRAs. In other words: there is no guarantee for
83       data-correctness.
84
85       When "pre-filling" a RRD file, the structure of the new file must be
86       specified as usual using DS and RRA specifications as outlined below.
87       Data will be taken from source files based on DS names and types and in
88       the order the source files are specified in. Data sources with the same
89       name from different source files will be combined to form a new data
90       source. Generally, for any point in time the new RRD file will cover
91       after its creation, data from only one source file will have been used
92       for pre-filling. However, data from multiple sources may be combined if
93       it refers to different times or an earlier named source file holds
94       unknown data for a time where a later one holds known data.
95
96       If this automatic data selection is not desired, the DS syntax allows
97       one to specify a mapping of target and source data sources for
98       prefilling. This syntax allows one to rename data sources and to
99       restrict prefilling for a DS to only use data from a single source
100       file.
101
102       Prefilling currently only works reliably for RRAs using one of the
103       classic consolidation functions, that is one of: AVERAGE, MIN, MAX,
104       LAST. It might also currently have problems with COMPUTE data sources.
105
106       Note that the act of prefilling during create is similar to a lot of
107       the operations available via the tune command, but using create syntax.
108
109   DS:ds-name[=mapped-ds-name[[source-index]]]:DST:dst arguments
110       A single RRD can accept input from several data sources (DS), for
111       example incoming and outgoing traffic on a specific communication line.
112       With the DS configuration option you must define some basic properties
113       of each data source you want to store in the RRD.
114
115       ds-name is the name you will use to reference this particular data
116       source from an RRD. A ds-name must be 1 to 19 characters long in the
117       characters [a-zA-Z0-9_].
118
119       DST defines the Data Source Type. The remaining arguments of a data
120       source entry depend on the data source type. For GAUGE, COUNTER,
121       DERIVE, DCOUNTER, DDERIVE and ABSOLUTE the format for a data source
122       entry is:
123
124       DS:ds-name:{GAUGE | COUNTER | DERIVE | DCOUNTER | DDERIVE |
125       ABSOLUTE}:heartbeat:min:max
126
127       For COMPUTE data sources, the format is:
128
129       DS:ds-name:COMPUTE:rpn-expression
130
131       In order to decide which data source type to use, review the
132       definitions that follow. Also consult the section on "HOW TO MEASURE"
133       for further insight.
134
135       GAUGE
136           is for things like temperatures or number of people in a room or
137           the value of a RedHat share.
138
139       COUNTER
140           is for continuous incrementing counters like the ifInOctets counter
141           in a router. The COUNTER data source assumes that the counter never
142           decreases, except when a counter overflows.  The update function
143           takes the overflow into account.  The counter is stored as a per-
144           second rate. When the counter overflows, RRDtool checks if the
145           overflow happened at the 32bit or 64bit border and acts accordingly
146           by adding an appropriate value to the result.
147
148       DCOUNTER
149           the same as COUNTER, but for quantities expressed as double-
150           precision floating point number.  Could be used to track quantities
151           that increment by non-integer numbers, i.e. number of seconds that
152           some routine has taken to run, total weight processed by some
153           technology equipment etc.  The only substantial difference is that
154           DCOUNTER can either be upward counting or downward counting, but
155           not both at the same time.  The current direction is detected
156           automatically on the second non-undefined counter update and any
157           further change in the direction is considered a reset.  The new
158           direction is determined and locked in by the second update after
159           reset and its difference to the value at reset.
160
161       DERIVE
162           will store the derivative of the line going from the last to the
163           current value of the data source. This can be useful for gauges,
164           for example, to measure the rate of people entering or leaving a
165           room. Internally, derive works exactly like COUNTER but without
166           overflow checks. So if your counter does not reset at 32 or 64 bit
167           you might want to use DERIVE and combine it with a MIN value of 0.
168
169       DDERIVE
170           the same as DERIVE, but for quantities expressed as double-
171           precision floating point number.
172
173           NOTE on COUNTER vs DERIVE
174
175           by Don Baarda <don.baarda@baesystems.com>
176
177           If you cannot tolerate ever mistaking the occasional counter reset
178           for a legitimate counter wrap, and would prefer "Unknowns" for all
179           legitimate counter wraps and resets, always use DERIVE with min=0.
180           Otherwise, using COUNTER with a suitable max will return correct
181           values for all legitimate counter wraps, mark some counter resets
182           as "Unknown", but can mistake some counter resets for a legitimate
183           counter wrap.
184
185           For a 5 minute step and 32-bit counter, the probability of
186           mistaking a counter reset for a legitimate wrap is arguably about
187           0.8% per 1Mbps of maximum bandwidth. Note that this equates to 80%
188           for 100Mbps interfaces, so for high bandwidth interfaces and a
189           32bit counter, DERIVE with min=0 is probably preferable. If you are
190           using a 64bit counter, just about any max setting will eliminate
191           the possibility of mistaking a reset for a counter wrap.
192
193       ABSOLUTE
194           is for counters which get reset upon reading. This is used for fast
195           counters which tend to overflow. So instead of reading them
196           normally you reset them after every read to make sure you have a
197           maximum time available before the next overflow. Another usage is
198           for things you count like number of messages since the last update.
199
200       COMPUTE
201           is for storing the result of a formula applied to other data
202           sources in the RRD. This data source is not supplied a value on
203           update, but rather its Primary Data Points (PDPs) are computed from
204           the PDPs of the data sources according to the rpn-expression that
205           defines the formula. Consolidation functions are then applied
206           normally to the PDPs of the COMPUTE data source (that is the rpn-
207           expression is only applied to generate PDPs). In database software,
208           such data sets are referred to as "virtual" or "computed" columns.
209
210       heartbeat defines the maximum number of seconds that may pass between
211       two updates of this data source before the value of the data source is
212       assumed to be *UNKNOWN*.
213
214       min and max define the expected range values for data supplied by a
215       data source. If min and/or max are specified any value outside the
216       defined range will be regarded as *UNKNOWN*. If you do not know or care
217       about min and max, set them to U for unknown. Note that min and max
218       always refer to the processed values of the DS. For a traffic-COUNTER
219       type DS this would be the maximum and minimum data-rate expected from
220       the device.
221
222       If information on minimal/maximal expected values is available, always
223       set the min and/or max properties. This will help RRDtool in doing a
224       simple sanity check on the data supplied when running update.
225
226       rpn-expression defines the formula used to compute the PDPs of a
227       COMPUTE data source from other data sources in the same <RRD>. It is
228       similar to defining a CDEF argument for the graph command. Please refer
229       to that manual page for a list and description of RPN operations
230       supported. For COMPUTE data sources, the following RPN operations are
231       not supported: COUNT, PREV, TIME, and LTIME. In addition, in defining
232       the RPN expression, the COMPUTE data source may only refer to the names
233       of data source listed previously in the create command. This is similar
234       to the restriction that CDEFs must refer only to DEFs and CDEFs
235       previously defined in the same graph command.
236
237       When pre-filling the new RRD file using one or more source RRDs, the DS
238       specification may hold an optional mapping after the DS name. This
239       takes the form of an equal sign followed by a mapped-to DS name and an
240       optional source index enclosed in square brackets.
241
242       For example, the DS
243
244        DS:a=b[2]:GAUGE:120:0:U
245
246       specifies that the DS named a should be pre-filled from the DS named b
247       in the second listed source file (source indices are 1-based).
248
249   RRA:CF:cf arguments
250       The purpose of an RRD is to store data in the round robin archives
251       (RRA). An archive consists of a number of data values or statistics for
252       each of the defined data-sources (DS) and is defined with an RRA line.
253
254       When data is entered into an RRD, it is first fit into time slots of
255       the length defined with the -s option, thus becoming a primary data
256       point.
257
258       The data is also processed with the consolidation function (CF) of the
259       archive. There are several consolidation functions that consolidate
260       primary data points via an aggregate function: AVERAGE, MIN, MAX, LAST.
261
262       AVERAGE
263           the average of the data points is stored.
264
265       MIN the smallest of the data points is stored.
266
267       MAX the largest of the data points is stored.
268
269       LAST
270           the last data points is used.
271
272       Note that data aggregation inevitably leads to loss of precision and
273       information. The trick is to pick the aggregate function such that the
274       interesting properties of your data is kept across the aggregation
275       process.
276
277       The format of RRA line for these consolidation functions is:
278
279       RRA:{AVERAGE | MIN | MAX | LAST}:xff:steps:rows
280
281       xff The xfiles factor defines what part of a consolidation interval may
282       be made up from *UNKNOWN* data while the consolidated value is still
283       regarded as known. It is given as the ratio of allowed *UNKNOWN* PDPs
284       to the number of PDPs in the interval. Thus, it ranges from 0 to 1
285       (exclusive).
286
287       steps defines how many of these primary data points are used to build a
288       consolidated data point which then goes into the archive.  See also
289       "STEP, HEARTBEAT, and Rows As Durations".
290
291       rows defines how many generations of data values are kept in an RRA.
292       Obviously, this has to be greater than zero.  See also "STEP,
293       HEARTBEAT, and Rows As Durations".
294

Aberrant Behavior Detection with Holt-Winters Forecasting

296       In addition to the aggregate functions, there are a set of specialized
297       functions that enable RRDtool to provide data smoothing (via the Holt-
298       Winters forecasting algorithm), confidence bands, and the flagging
299       aberrant behavior in the data source time series:
300
301RRA:HWPREDICT:rows:alpha:beta:seasonal period[:rra-num]
302
303RRA:MHWPREDICT:rows:alpha:beta:seasonal period[:rra-num]
304
305RRA:SEASONAL:seasonal period:gamma:rra-
306           num[:smoothing-window=fraction]
307
308RRA:DEVSEASONAL:seasonal period:gamma:rra-
309           num[:smoothing-window=fraction]
310
311RRA:DEVPREDICT:rows:rra-num
312
313RRA:FAILURES:rows:threshold:window length:rra-num
314
315       These RRAs differ from the true consolidation functions in several
316       ways.  First, each of the RRAs is updated once for every primary data
317       point.  Second, these RRAs are interdependent. To generate real-time
318       confidence bounds, a matched set of SEASONAL, DEVSEASONAL, DEVPREDICT,
319       and either HWPREDICT or MHWPREDICT must exist. Generating smoothed
320       values of the primary data points requires a SEASONAL RRA and either an
321       HWPREDICT or MHWPREDICT RRA. Aberrant behavior detection requires
322       FAILURES, DEVSEASONAL, SEASONAL, and either HWPREDICT or MHWPREDICT.
323
324       The predicted, or smoothed, values are stored in the HWPREDICT or
325       MHWPREDICT RRA. HWPREDICT and MHWPREDICT are actually two variations on
326       the Holt-Winters method. They are interchangeable. Both attempt to
327       decompose data into three components: a baseline, a trend, and a
328       seasonal coefficient.  HWPREDICT adds its seasonal coefficient to the
329       baseline to form a prediction, whereas MHWPREDICT multiplies its
330       seasonal coefficient by the baseline to form a prediction. The
331       difference is noticeable when the baseline changes significantly in the
332       course of a season; HWPREDICT will predict the seasonality to stay
333       constant as the baseline changes, but MHWPREDICT will predict the
334       seasonality to grow or shrink in proportion to the baseline. The proper
335       choice of method depends on the thing being modeled. For simplicity,
336       the rest of this discussion will refer to HWPREDICT, but MHWPREDICT may
337       be substituted in its place.
338
339       The predicted deviations are stored in DEVPREDICT (think a standard
340       deviation which can be scaled to yield a confidence band). The FAILURES
341       RRA stores binary indicators. A 1 marks the indexed observation as
342       failure; that is, the number of confidence bounds violations in the
343       preceding window of observations met or exceeded a specified threshold.
344       An example of using these RRAs to graph confidence bounds and failures
345       appears in rrdgraph.
346
347       The SEASONAL and DEVSEASONAL RRAs store the seasonal coefficients for
348       the Holt-Winters forecasting algorithm and the seasonal deviations,
349       respectively.  There is one entry per observation time point in the
350       seasonal cycle. For example, if primary data points are generated every
351       five minutes and the seasonal cycle is 1 day, both SEASONAL and
352       DEVSEASONAL will have 288 rows.
353
354       In order to simplify the creation for the novice user, in addition to
355       supporting explicit creation of the HWPREDICT, SEASONAL, DEVPREDICT,
356       DEVSEASONAL, and FAILURES RRAs, the RRDtool create command supports
357       implicit creation of the other four when HWPREDICT is specified alone
358       and the final argument rra-num is omitted.
359
360       rows specifies the length of the RRA prior to wrap around. Remember
361       that there is a one-to-one correspondence between primary data points
362       and entries in these RRAs. For the HWPREDICT CF, rows should be larger
363       than the seasonal period. If the DEVPREDICT RRA is implicitly created,
364       the default number of rows is the same as the HWPREDICT rows argument.
365       If the FAILURES RRA is implicitly created, rows will be set to the
366       seasonal period argument of the HWPREDICT RRA. Of course, the RRDtool
367       resize command is available if these defaults are not sufficient and
368       the creator wishes to avoid explicit creations of the other specialized
369       function RRAs.
370
371       seasonal period specifies the number of primary data points in a
372       seasonal cycle. If SEASONAL and DEVSEASONAL are implicitly created,
373       this argument for those RRAs is set automatically to the value
374       specified by HWPREDICT. If they are explicitly created, the creator
375       should verify that all three seasonal period arguments agree.
376
377       alpha is the adaption parameter of the intercept (or baseline)
378       coefficient in the Holt-Winters forecasting algorithm. See rrdtool for
379       a description of this algorithm. alpha must lie between 0 and 1. A
380       value closer to 1 means that more recent observations carry greater
381       weight in predicting the baseline component of the forecast. A value
382       closer to 0 means that past history carries greater weight in
383       predicting the baseline component.
384
385       beta is the adaption parameter of the slope (or linear trend)
386       coefficient in the Holt-Winters forecasting algorithm. beta must lie
387       between 0 and 1 and plays the same role as alpha with respect to the
388       predicted linear trend.
389
390       gamma is the adaption parameter of the seasonal coefficients in the
391       Holt-Winters forecasting algorithm (HWPREDICT) or the adaption
392       parameter in the exponential smoothing update of the seasonal
393       deviations. It must lie between 0 and 1. If the SEASONAL and
394       DEVSEASONAL RRAs are created implicitly, they will both have the same
395       value for gamma: the value specified for the HWPREDICT alpha argument.
396       Note that because there is one seasonal coefficient (or deviation) for
397       each time point during the seasonal cycle, the adaptation rate is much
398       slower than the baseline. Each seasonal coefficient is only updated (or
399       adapts) when the observed value occurs at the offset in the seasonal
400       cycle corresponding to that coefficient.
401
402       If SEASONAL and DEVSEASONAL RRAs are created explicitly, gamma need not
403       be the same for both. Note that gamma can also be changed via the
404       RRDtool tune command.
405
406       smoothing-window specifies the fraction of a season that should be
407       averaged around each point. By default, the value of smoothing-window
408       is 0.05, which means each value in SEASONAL and DEVSEASONAL will be
409       occasionally replaced by averaging it with its (seasonal period*0.05)
410       nearest neighbors.  Setting smoothing-window to zero will disable the
411       running-average smoother altogether.
412
413       rra-num provides the links between related RRAs. If HWPREDICT is
414       specified alone and the other RRAs are created implicitly, then there
415       is no need to worry about this argument. If RRAs are created
416       explicitly, then carefully pay attention to this argument. For each RRA
417       which includes this argument, there is a dependency between that RRA
418       and another RRA. The rra-num argument is the 1-based index in the order
419       of RRA creation (that is, the order they appear in the create command).
420       The dependent RRA for each RRA requiring the rra-num argument is listed
421       here:
422
423       •   HWPREDICT rra-num is the index of the SEASONAL RRA.
424
425       •   SEASONAL rra-num is the index of the HWPREDICT RRA.
426
427       •   DEVPREDICT rra-num is the index of the DEVSEASONAL RRA.
428
429       •   DEVSEASONAL rra-num is the index of the HWPREDICT RRA.
430
431       •   FAILURES rra-num is the index of the DEVSEASONAL RRA.
432
433       threshold is the minimum number of violations (observed values outside
434       the confidence bounds) within a window that constitutes a failure. If
435       the FAILURES RRA is implicitly created, the default value is 7.
436
437       window length is the number of time points in the window. Specify an
438       integer greater than or equal to the threshold and less than or equal
439       to 28.  The time interval this window represents depends on the
440       interval between primary data points. If the FAILURES RRA is implicitly
441       created, the default value is 9.
442

STEP, HEARTBEAT, and Rows As Durations

444       Traditionally RRDtool specified PDP intervals in seconds, and most
445       other values as either seconds or PDP counts.  This made the
446       specification for databases rather opaque; for example
447
448        rrdtool create power.rrd \
449          --start now-2h --step 1 \
450          DS:watts:GAUGE:300:0:24000 \
451          RRA:AVERAGE:0.5:1:864000 \
452          RRA:AVERAGE:0.5:60:129600 \
453          RRA:AVERAGE:0.5:3600:13392 \
454          RRA:AVERAGE:0.5:86400:3660
455
456       creates a database of power values collected once per second, with a
457       five minute (300 second) heartbeat, and four RRAs: ten days of one
458       second, 90 days of one minute, 18 months of one hour, and ten years of
459       one day averages.
460
461       Step, heartbeat, and PDP counts and rows may also be specified as
462       durations, which are positive integers with a single-character suffix
463       that specifies a scaling factor.  See "rrd_scaled_duration" in librrd
464       for scale factors of the supported suffixes: "s" (seconds), "m"
465       (minutes), "h" (hours), "d" (days), "w" (weeks), "M" (months), and "y"
466       (years).
467
468       Scaled step and heartbeat values (which are natively durations in
469       seconds) are used directly, while consolidation function row arguments
470       are divided by their step to produce the number of rows.
471
472       With this feature the same specification as above can be written as:
473
474        rrdtool create power.rrd \
475          --start now-2h --step 1s \
476          DS:watts:GAUGE:5m:0:24000 \
477          RRA:AVERAGE:0.5:1s:10d \
478          RRA:AVERAGE:0.5:1m:90d \
479          RRA:AVERAGE:0.5:1h:18M \
480          RRA:AVERAGE:0.5:1d:10y
481

The HEARTBEAT and the STEP

483       Here is an explanation by Don Baarda on the inner workings of RRDtool.
484       It may help you to sort out why all this *UNKNOWN* data is popping up
485       in your databases:
486
487       RRDtool gets fed samples/updates at arbitrary times. From these it
488       builds Primary Data Points (PDPs) on every "step" interval. The PDPs
489       are then accumulated into the RRAs.
490
491       The "heartbeat" defines the maximum acceptable interval between
492       samples/updates. If the interval between samples is less than
493       "heartbeat", then an average rate is calculated and applied for that
494       interval. If the interval between samples is longer than "heartbeat",
495       then that entire interval is considered "unknown". Note that there are
496       other things that can make a sample interval "unknown", such as the
497       rate exceeding limits, or a sample that was explicitly marked as
498       unknown.
499
500       The known rates during a PDP's "step" interval are used to calculate an
501       average rate for that PDP. If the total "unknown" time accounts for
502       more than half the "step", the entire PDP is marked as "unknown". This
503       means that a mixture of known and "unknown" sample times in a single
504       PDP "step" may or may not add up to enough "known" time to warrant a
505       known PDP.
506
507       The "heartbeat" can be short (unusual) or long (typical) relative to
508       the "step" interval between PDPs. A short "heartbeat" means you require
509       multiple samples per PDP, and if you don't get them mark the PDP
510       unknown. A long heartbeat can span multiple "steps", which means it is
511       acceptable to have multiple PDPs calculated from a single sample. An
512       extreme example of this might be a "step" of 5 minutes and a
513       "heartbeat" of one day, in which case a single sample every day will
514       result in all the PDPs for that entire day period being set to the same
515       average rate. -- Don Baarda <don.baarda@baesystems.com>
516
517              time|
518              axis|
519        begin__|00|
520               |01|
521              u|02|----* sample1, restart "hb"-timer
522              u|03|   /
523              u|04|  /
524              u|05| /
525              u|06|/     "hbt" expired
526              u|07|
527               |08|----* sample2, restart "hb"
528               |09|   /
529               |10|  /
530              u|11|----* sample3, restart "hb"
531              u|12|   /
532              u|13|  /
533        step1_u|14| /
534              u|15|/     "swt" expired
535              u|16|
536               |17|----* sample4, restart "hb", create "pdp" for step1 =
537               |18|   /  = unknown due to 10 "u" labeled secs > 0.5 * step
538               |19|  /
539               |20| /
540               |21|----* sample5, restart "hb"
541               |22|   /
542               |23|  /
543               |24|----* sample6, restart "hb"
544               |25|   /
545               |26|  /
546               |27|----* sample7, restart "hb"
547        step2__|28|   /
548               |22|  /
549               |23|----* sample8, restart "hb", create "pdp" for step1, create "cdp"
550               |24|   /
551               |25|  /
552
553       graphics by vladimir.lavrov@desy.de.
554

HOW TO MEASURE

556       Here are a few hints on how to measure:
557
558       Temperature
559           Usually you have some type of meter you can read to get the
560           temperature.  The temperature is not really connected with a time.
561           The only connection is that the temperature reading happened at a
562           certain time. You can use the GAUGE data source type for this.
563           RRDtool will then record your reading together with the time.
564
565       Mail Messages
566           Assume you have a method to count the number of messages
567           transported by your mail server in a certain amount of time, giving
568           you data like '5 messages in the last 65 seconds'. If you look at
569           the count of 5 like an ABSOLUTE data type you can simply update the
570           RRD with the number 5 and the end time of your monitoring period.
571           RRDtool will then record the number of messages per second. If at
572           some later stage you want to know the number of messages
573           transported in a day, you can get the average messages per second
574           from RRDtool for the day in question and multiply this number with
575           the number of seconds in a day. Because all math is run with
576           Doubles, the precision should be acceptable.
577
578       It's always a Rate
579           RRDtool stores rates in amount/second for COUNTER, DERIVE,
580           DCOUNTER, DDERIVE and ABSOLUTE data.  When you plot the data, you
581           will get on the y axis amount/second which you might be tempted to
582           convert to an absolute amount by multiplying by the delta-time
583           between the points. RRDtool plots continuous data, and as such is
584           not appropriate for plotting absolute amounts as for example "total
585           bytes" sent and received in a router. What you probably want is
586           plot rates that you can scale to bytes/hour, for example, or plot
587           absolute amounts with another tool that draws bar-plots, where the
588           delta-time is clear on the plot for each point (such that when you
589           read the graph you see for example GB on the y axis, days on the x
590           axis and one bar for each day).
591

EXAMPLE

593        rrdtool create temperature.rrd --step 300 \
594         DS:temp:GAUGE:600:-273:5000 \
595         RRA:AVERAGE:0.5:1:1200 \
596         RRA:MIN:0.5:12:2400 \
597         RRA:MAX:0.5:12:2400 \
598         RRA:AVERAGE:0.5:12:2400
599
600       This sets up an RRD called temperature.rrd which accepts one
601       temperature value every 300 seconds. If no new data is supplied for
602       more than 600 seconds, the temperature becomes *UNKNOWN*.  The minimum
603       acceptable value is -273 and the maximum is 5'000.
604
605       A few archive areas are also defined. The first stores the temperatures
606       supplied for 100 hours (1'200 * 300 seconds = 100 hours). The second
607       RRA stores the minimum temperature recorded over every hour (12 * 300
608       seconds = 1 hour), for 100 days (2'400 hours). The third and the fourth
609       RRA's do the same for the maximum and average temperature,
610       respectively.
611

EXAMPLE 2

613        rrdtool create monitor.rrd --step 300        \
614          DS:ifOutOctets:COUNTER:1800:0:4294967295   \
615          RRA:AVERAGE:0.5:1:2016                     \
616          RRA:HWPREDICT:1440:0.1:0.0035:288
617
618       This example is a monitor of a router interface. The first RRA tracks
619       the traffic flow in octets; the second RRA generates the specialized
620       functions RRAs for aberrant behavior detection. Note that the rra-num
621       argument of HWPREDICT is missing, so the other RRAs will implicitly be
622       created with default parameter values. In this example, the forecasting
623       algorithm baseline adapts quickly; in fact the most recent one hour of
624       observations (each at 5 minute intervals) accounts for 75% of the
625       baseline prediction. The linear trend forecast adapts much more slowly.
626       Observations made during the last day (at 288 observations per day)
627       account for only 65% of the predicted linear trend. Note: these
628       computations rely on an exponential smoothing formula described in the
629       LISA 2000 paper.
630
631       The seasonal cycle is one day (288 data points at 300 second
632       intervals), and the seasonal adaption parameter will be set to 0.1. The
633       RRD file will store 5 days (1'440 data points) of forecasts and
634       deviation predictions before wrap around. The file will store 1 day (a
635       seasonal cycle) of 0-1 indicators in the FAILURES RRA.
636
637       The same RRD file and RRAs are created with the following command,
638       which explicitly creates all specialized function RRAs using "STEP,
639       HEARTBEAT, and Rows As Durations".
640
641        rrdtool create monitor.rrd --step 5m \
642          DS:ifOutOctets:COUNTER:30m:0:4294967295 \
643          RRA:AVERAGE:0.5:1:2016 \
644          RRA:HWPREDICT:5d:0.1:0.0035:1d:3 \
645          RRA:SEASONAL:1d:0.1:2 \
646          RRA:DEVSEASONAL:1d:0.1:2 \
647          RRA:DEVPREDICT:5d:5 \
648          RRA:FAILURES:1d:7:9:5
649
650       Of course, explicit creation need not replicate implicit create, a
651       number of arguments could be changed.
652

EXAMPLE 3

654        rrdtool create proxy.rrd --step 300 \
655          DS:Requests:DERIVE:1800:0:U  \
656          DS:Duration:DERIVE:1800:0:U  \
657          DS:AvgReqDur:COMPUTE:Duration,Requests,0,EQ,1,Requests,IF,/ \
658          RRA:AVERAGE:0.5:1:2016
659
660       This example is monitoring the average request duration during each 300
661       sec interval for requests processed by a web proxy during the interval.
662       In this case, the proxy exposes two counters, the number of requests
663       processed since boot and the total cumulative duration of all processed
664       requests. Clearly these counters both have some rollover point, but
665       using the DERIVE data source also handles the reset that occurs when
666       the web proxy is stopped and restarted.
667
668       In the RRD, the first data source stores the requests per second rate
669       during the interval. The second data source stores the total duration
670       of all requests processed during the interval divided by 300. The
671       COMPUTE data source divides each PDP of the AccumDuration by the
672       corresponding PDP of TotalRequests and stores the average request
673       duration. The remainder of the RPN expression handles the divide by
674       zero case.
675

SECURITY

677       Note that new rrd files will have the permission 0644 regardless of
678       your umask setting. If a file with the same name previously exists, its
679       permission settings will be copied to the new file.
680

AUTHORS

682       Tobias Oetiker <tobi@oetiker.ch>, Peter Stamfest <peter@stamfest.at>
683
684
685
6861.8.0                             2022-03-14                      RRDCREATE(1)
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