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
17 depending 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.
43 In order to get RRDtool to fetch anything other than the finest
45 boundaries that are multiples of the desired resolution. Consider the
46 following example:
48 rrdtool create subdata.rrd -s 10 DS:ds0:GAUGE:300:0:U \
49 RRA:AVERAGE:0.5:30:3600 \
50 RRA:AVERAGE:0.5:90:1200 \
51 RRA:AVERAGE:0.5:360:1200 \
52 RRA:MAX:0.5:360:1200 \
53 RRA:AVERAGE:0.5:8640:600 \
54 RRA:MAX:0.5:8640:600
56 This RRD collects data every 10 seconds and stores its averages over 5
57 minutes, 15 minutes, 1 hour, and 1 day, as well as the maxima for 1
58 hour and 1 day.
60 Consider now that you want to fetch the 15 minute average data for the
61 last hour. You might try
63 rrdtool fetch subdata.rrd AVERAGE -r 900 -s -1h
66 the 15 minute RRA. Therefore, the highest resolution RRA, i.e. 5 minute
67 averages, will be chosen which in this case is not what you want.
69 Hence, make sure that
71 1. both start and end time are a multiple of 900
73 2. both start and end time are within the desired RRA
75 So, if time now is called "t", do
77 end time == int(t/900)*900,
78 start time == end time - 1hour,
79 resolution == 900.
81 Using the bash shell, this could look be:
83 TIME=$(date +%s)
84 RRDRES=900
85 rrdtool fetch subdata.rrd AVERAGE -r $RRDRES \
86 -e $(($TIME/$RRDRES*$RRDRES)) -s e-1h
88 Or in Perl:
90 perl -e '$ctime = time; $rrdres = 900; \
91 system "rrdtool fetch subdata.rrd AVERAGE \
92 -r $rrdres -e @{[int($ctime/$rrdres)*$rrdres]} -s e-1h"'
94 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
95 Apart from the traditional _\bS_\be_\bc_\bo_\bn_\bd_\bs _\bs_\bi_\bn_\bc_\be _\be_\bp_\bo_\bc_\bh, RRDtool does also
96 understand at-style time specification. The specification is called
98 ways to specify time to run your job at a certain date and time. The
99 at-style specification consists of two parts: the T\bTI\bIM\bME\bE R\bRE\bEF\bFE\bER\bRE\bEN\bNC\bCE\bE
102 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
103 The time reference specification is used, well, to establish a
104 reference moment in time (to which the time offset is then applied to).
106 On its own part, time reference consists of a _\bt_\bi_\bm_\be_\b-_\bo_\bf_\b-_\bd_\ba_\by reference
109 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
111 day are understood as well, including m\bmi\bid\bdn\bni\big\bgh\bht\bt (00:00), n\bno\boo\bon\bn (12:00)
114 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
116 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,
117 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
118 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.
121 single-number date is interpreted as MMDD[YY]YY.
123 _\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
124 as well.
129 the start (end) time for those tools that use these categories
132 Month and day of the week names can be used in their naturally
133 abbreviated form (e.g., Dec for December, Sun for Sunday, etc.). The
137 The time offset specification is used to add/subtract certain time
140 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.
141 These units can be used in singular or plural form, and abbreviated
142 naturally or to a single letter (e.g. +3days, -1wk, -3y). Several time
143 units can be combined (e.g., -5mon1w2d) or concatenated (e.g., -5h45min
144 = -5h-45min = -6h+15min = -7h+1h30m-15min, etc.)
147 will end with the time offset that may vary depending on your time
148 reference, because all those time units have no single well defined
149 time interval value (1 year contains either 365 or 366 days, 1 month is
150 28 to 31 days long, and even 1 day may be not equal to 24 hours twice a
151 year, when DST-related clock adjustments take place). To cope with
152 this, when you use days, weeks, months, or years as your time offset
153 units your time reference date is adjusted accordingly without too much
155 will take care of this later). This may lead to some surprising (or
156 even invalid!) results, e.g. 'May 31 -1month' = 'Apr 31' (meaningless)
158 Mar 29 1999 -1 day' yields '3:30am Mar 28 1999' (Sunday) which is an
159 invalid time/date combination (because of 3am -> 4am DST forward clock
160 adjustment, see the below example).
162 In contrast, hours, minutes, and seconds are well defined time
163 intervals, and these are guaranteed to always produce time offsets
164 exactly as specified (e.g. for EET timezone, '8:00 Mar 27 1999 +2 days'
165 = '8:00 Mar 29 1999', but since there is 1-hour DST forward clock
166 adjustment that occurs around 3:00 Mar 28 1999, the actual time
167 interval between 8:00 Mar 27 1999 and 8:00 Mar 29 1999 equals 47 hours;
168 on the other hand, '8:00 Mar 27 1999 +48 hours' = '9:00 Mar 29 1999',
169 as expected)
171 _\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.
172 To disambiguate them, the parser tries to read your mind :) by applying
173 the following two heuristics:
175 1. If m\bm is used in context of (i.e. right after the) years, months,
177 hours, minutes, and seconds it means minutes. (e.g., in -1y6m or
182 is guessed from the number it directly follows. Currently, if the
183 number's absolute value is below 25 it is assumed that m\bm means
184 m\bmo\bon\bnt\bth\bhs\bs, otherwise it is treated as m\bmi\bin\bnu\but\bte\bes\bs. (e.g., -25m == -25
185 minutes, while +24m == +24 months)
187 _\bF_\bi_\bn_\ba_\bl _\bN_\bO_\bT_\bE_\bS: Time specification is case-insensitive. Whitespace can be
188 inserted freely or omitted altogether. There are, however, cases when
189 whitespace is required (e.g., 'midnight Thu'). In this case you should
190 either quote the whole phrase to prevent it from being taken apart by
191 your shell or use '_' (underscore) or ',' (comma) which also count as
192 whitespace (e.g., midnight_Thu or midnight,Thu).
194 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
197 _\b-_\b1_\bm_\bo_\bn_\bt_\bh or _\b-_\b1_\bm -- current time of day, only a month before (may yield
198 surprises, see NOTE3 above).
200 _\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
205 _\b1_\b2_\b/_\b3_\b1_\b/_\b9_\b9 _\b1_\b1_\b:_\b5_\b9_\bp_\bm -- 1 minute to the year 2000 for imperialists.
209 _\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
210 time specification).
212 _\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
213 time specification).
216 as well).
218 _\b1_\b9_\b9_\b7_\b0_\b7_\b0_\b3 _\b1_\b2_\b:_\b4_\b5 -- 12:45 July 3th, 1997 (my favorite, and its even got
219 an ISO number (8601)).
222 Tobias Oetiker <tobi@oetiker.ch>
226 1.3.8 2008-03-15 RRDFETCH(1)