1 RRDFETCH(1) rrdtool RRDFETCH(1)
6 rrdfetch - Fetch data from an RRD.
9 r\brr\brd\bdt\bto\boo\bol\bl f\bfe\bet\btc\bch\bh _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be _\bC_\bF [-\b--\b-r\bre\bes\bso\bol\blu\but\bti\bio\bon\bn|-\b-r\br _\br_\be_\bs_\bo_\bl_\bu_\bt_\bi_\bo_\bn]
10 [-\b--\b-s\bst\bta\bar\brt\bt|-\b-s\bs _\bs_\bt_\ba_\br_\bt] [-\b--\b-e\ben\bnd\bd|-\b-e\be _\be_\bn_\bd]
14 get data from R\bRR\bRD\bDs. f\bfe\bet\btc\bch\bh will analyze the R\bRR\bRD\bD and try to retrieve the
15 data in the resolution requested. The data fetched is printed to std-
16 out. _\b*_\bU_\bN_\bK_\bN_\bO_\bW_\bN_\b* data is often represented by the string "NaN" depending
17 on your OS's printf function.
23 to fetch (AVERAGE,MIN,MAX,LAST)
25 -\b--\b-r\bre\bes\bso\bol\blu\but\bti\bio\bon\bn|-\b-r\br _\br_\be_\bs_\bo_\bl_\bu_\bt_\bi_\bo_\bn (default is the highest resolution)
26 the interval you want the values to have (seconds per value).
31 start of the time series. A time in seconds since epoch
32 (1970-01-01) is required. Negative numbers are relative to the
33 current time. By default, one day worth of data will be
34 fetched. See also AT-STYLE TIME SPECIFICATION section for a
35 detailed explanation on ways to specify the start time.
38 the end of the time series in seconds since epoch. See also AT-
39 STYLE TIME SPECIFICATION section for a detailed explanation of
40 how to specify the end time.
44 In order to get RRDtool to fetch anything other than the finest resolu-
46 that are multiples of the desired resolution. Consider the following
47 example:
49 rrdtool create subdata.rrd -s 10 DS:ds0:GAUGE:300:0:U \
50 RRA:AVERAGE:0.5:30:3600 \
51 RRA:AVERAGE:0.5:90:1200 \
52 RRA:AVERAGE:0.5:360:1200 \
53 RRA:MAX:0.5:360:1200 \
54 RRA:AVERAGE:0.5:8640:600 \
55 RRA:MAX:0.5:8640:600
57 This RRD collects data every 10 seconds and stores its averages over 5
58 minutes, 15 minutes, 1 hour, and 1 day, as well as the maxima for 1
59 hour and 1 day.
61 Consider now that you want to fetch the 15 minute average data for the
62 last hour. You might try
64 rrdtool fetch subdata.rrd AVERAGE -r 900 -s -1h
67 the 15 minute RRA. Therefore, the highest resolution RRA, i.e. 5 minute
68 averages, will be chosen which in this case is not what you want.
70 Hence, make sure that
72 1. both start and end time are a multiple of 900
74 2. both start and end time are within the desired RRA
76 So, if time now is called "t", do
78 end time == int(t/900)*900,
79 start time == end time - 1hour,
80 resolution == 900.
82 Using the bash shell, this could look be:
84 TIME=$(date +%s)
85 RRDRES=900
86 rrdtool fetch subdata.rrd AVERAGE -r $RRDRES \
87 -e $(($TIME/$RRDRES*$RRDRES)) -s e-1h
89 Or in Perl:
91 perl -e '$ctime = time; $rrdres = 900; \
92 system "rrdtool fetch subdata.rrd AVERAGE \
93 -r $rrdres -e @{[int($ctime/$rrdres)*$rrdres]} -s e-1h"'
95 A\bAT\bT-\b-S\bST\bTY\bYL\bLE\bE T\bTI\bIM\bME\bE S\bSP\bPE\bEC\bCI\bIF\bFI\bIC\bCA\bAT\bTI\bIO\bON\bN
97 Apart from the traditional _\bS_\be_\bc_\bo_\bn_\bd_\bs _\bs_\bi_\bn_\bc_\be _\be_\bp_\bo_\bc_\bh, RRDtool does also
98 understand at-style time specification. The specification is called
100 ways to specify time to run your job at a certain date and time. The
101 at-style specification consists of two parts: the T\bTI\bIM\bME\bE R\bRE\bEF\bFE\bER\bRE\bEN\bNC\bCE\bE speci-
104 T\bTI\bIM\bME\bE R\bRE\bEF\bFE\bER\bRE\bEN\bNC\bCE\bE S\bSP\bPE\bEC\bCI\bIF\bFI\bIC\bCA\bAT\bTI\bIO\bON\bN
106 The time reference specification is used, well, to establish a refer-
107 ence moment in time (to which the time offset is then applied to). When
109 own part, time reference consists of a _\bt_\bi_\bm_\be_\b-_\bo_\bf_\b-_\bd_\ba_\by reference (which
112 The _\bt_\bi_\bm_\be_\b-_\bo_\bf_\b-_\bd_\ba_\by can be specified as H\bHH\bH:\b:M\bMM\bM, H\bHH\bH.\b.M\bMM\bM, or just H\bHH\bH. You can
114 day are understood as well, including m\bmi\bid\bdn\bni\big\bgh\bht\bt (00:00), n\bno\boo\bon\bn (12:00)
117 The _\bd_\ba_\by can be specified as _\bm_\bo_\bn_\bt_\bh_\b-_\bn_\ba_\bm_\be _\bd_\ba_\by_\b-_\bo_\bf_\b-_\bt_\bh_\be_\b-_\bm_\bo_\bn_\bt_\bh and optional a
119 use _\bd_\ba_\by_\b-_\bo_\bf_\b-_\bw_\be_\be_\bk_\b-_\bn_\ba_\bm_\be (e.g. Monday), or one of the words: y\bye\bes\bst\bte\ber\brd\bda\bay\by,
120 t\bto\bod\bda\bay\by, t\bto\bom\bmo\bor\brr\bro\bow\bw. You can also specify the _\bd_\ba_\by as a full date in several
121 numerical formats, including M\bMM\bM/\b/D\bDD\bD/\b/[\b[Y\bYY\bY]\b]Y\bYY\bY, D\bDD\bD.\b.M\bMM\bM.\b.[\b[Y\bYY\bY]\b]Y\bYY\bY, or Y\bYY\bYY\bYY\bYM\bMM\bMD\bDD\bD.
124 gle-number date is interpreted as MMDD[YY]YY.
126 _\bN_\bO_\bT_\bE_\b2: if you specify the _\bd_\ba_\by in this way, the _\bt_\bi_\bm_\be_\b-_\bo_\bf_\b-_\bd_\ba_\by is REQUIRED
127 as well.
129 Finally, you can use the words n\bno\bow\bw, s\bst\bta\bar\brt\bt, or e\ben\bnd\bd as your time refer-
133 rrdgraph).
135 Month and day of the week names can be used in their naturally abbrevi-
136 ated form (e.g., Dec for December, Sun for Sunday, etc.). The words
141 The time offset specification is used to add/subtract certain time
144 the _\ba_\bm_\bo_\bu_\bn_\bt: y\bye\bea\bar\brs\bs, m\bmo\bon\bnt\bth\bhs\bs, w\bwe\bee\bek\bks\bs, d\bda\bay\bys\bs, h\bho\bou\bur\brs\bs, m\bmi\bin\bnu\but\bte\bes\bs, or s\bse\bec\bco\bon\bnd\bds\bs.
145 These units can be used in singular or plural form, and abbreviated
146 naturally or to a single letter (e.g. +3days, -1wk, -3y). Several time
147 units can be combined (e.g., -5mon1w2d) or concatenated (e.g., -5h45min
148 = -5h-45min = -6h+15min = -7h+1h30m-15min, etc.)
151 will end with the time offset that may vary depending on your time ref-
152 erence, because all those time units have no single well defined time
153 interval value (1 year contains either 365 or 366 days, 1 month is 28
154 to 31 days long, and even 1 day may be not equal to 24 hours twice a
155 year, when DST-related clock adjustments take place). To cope with
156 this, when you use days, weeks, months, or years as your time offset
157 units your time reference date is adjusted accordingly without too much
159 will take care of this later). This may lead to some surprising (or
160 even invalid!) results, e.g. 'May 31 -1month' = 'Apr 31' (meaningless)
162 Mar 29 1999 -1 day' yields '3:30am Mar 28 1999' (Sunday) which is an
163 invalid time/date combination (because of 3am -> 4am DST forward clock
164 adjustment, see the below example).
166 In contrast, hours, minutes, and seconds are well defined time inter-
167 vals, and these are guaranteed to always produce time offsets exactly
168 as specified (e.g. for EET timezone, '8:00 Mar 27 1999 +2 days' =
169 '8:00 Mar 29 1999', but since there is 1-hour DST forward clock adjust-
170 ment that occurs around 3:00 Mar 28 1999, the actual time interval
171 between 8:00 Mar 27 1999 and 8:00 Mar 29 1999 equals 47 hours; on the
172 other hand, '8:00 Mar 27 1999 +48 hours' = '9:00 Mar 29 1999', as
173 expected)
175 _\bN_\bO_\bT_\bE_\b4: The single-letter abbreviation for both m\bmo\bon\bnt\bth\bhs\bs and m\bmi\bin\bnu\but\bte\bes\bs is m\bm.
176 To disambiguate them, the parser tries to read your mind :) by applying
177 the following two heuristics:
179 1 If m\bm is used in context of (i.e. right after the) years, months,
181 hours, minutes, and seconds it means minutes. (e.g., in -1y6m or
186 is guessed from the number it directly follows. Currently, if the
187 number's absolute value is below 25 it is assumed that m\bm means
188 m\bmo\bon\bnt\bth\bhs\bs, otherwise it is treated as m\bmi\bin\bnu\but\bte\bes\bs. (e.g., -25m == -25 min-
189 utes, while +24m == +24 months)
191 _\bF_\bi_\bn_\ba_\bl _\bN_\bO_\bT_\bE_\bS: Time specification is case-insensitive. Whitespace can be
192 inserted freely or omitted altogether. There are, however, cases when
193 whitespace is required (e.g., 'midnight Thu'). In this case you should
194 either quote the whole phrase to prevent it from being taken apart by
195 your shell or use '_' (underscore) or ',' (comma) which also count as
196 whitespace (e.g., midnight_Thu or midnight,Thu).
198 T\bTI\bIM\bME\bE S\bSP\bPE\bEC\bCI\bIF\bFI\bIC\bCA\bAT\bTI\bIO\bON\bN E\bEX\bXA\bAM\bMP\bPL\bLE\bES\bS
202 _\b-_\b1_\bm_\bo_\bn_\bt_\bh or _\b-_\b1_\bm -- current time of day, only a month before (may yield
203 surprises, see NOTE3 above).
205 _\bn_\bo_\bo_\bn _\by_\be_\bs_\bt_\be_\br_\bd_\ba_\by _\b-_\b3_\bh_\bo_\bu_\br_\bs -- yesterday morning; can also be specified as
210 _\b1_\b2_\b/_\b3_\b1_\b/_\b9_\b9 _\b1_\b1_\b:_\b5_\b9_\bp_\bm -- 1 minute to the year 2000 for imperialists.
214 _\be_\bn_\bd_\b-_\b3_\bw_\be_\be_\bk_\bs or _\be_\b-_\b3_\bw -- 3 weeks before end time (may be used as start
215 time specification).
217 _\bs_\bt_\ba_\br_\bt_\b+_\b6_\bh_\bo_\bu_\br_\bs or _\bs_\b+_\b6_\bh -- 6 hours after start time (may be used as end
218 time specification).
221 as well).
223 _\b1_\b9_\b9_\b7_\b0_\b7_\b0_\b3 _\b1_\b2_\b:_\b4_\b5 -- 12:45 July 3th, 1997 (my favorite, and its even got
224 an ISO number (8601)).
227 Tobias Oetiker <tobi@oetiker.ch>
231 1.3.1 2008-03-15 RRDFETCH(1)