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] [-\b--\b-d\bda\bae\bem\bmo\bon\bn _\ba_\bd_\bd_\br_\be_\bs_\bs]
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.
43 Address of the rrdcached daemon. If specified, a "flush" com-
44 mand is sent to the server before reading the RRD files. This
46 figured to cache values for a long time. For a list of
49 rrdtool fetch --daemon unix:/var/run/rrdcached.sock /var/lib/rrd/foo.rrd AVERAGE
53 In order to get RRDtool to fetch anything other than the finest resolu-
55 that are multiples of the desired resolution. Consider the following
56 example:
58 rrdtool create subdata.rrd -s 10 DS:ds0:GAUGE:300:0:U \
59 RRA:AVERAGE:0.5:30:3600 \
60 RRA:AVERAGE:0.5:90:1200 \
61 RRA:AVERAGE:0.5:360:1200 \
62 RRA:MAX:0.5:360:1200 \
63 RRA:AVERAGE:0.5:8640:600 \
64 RRA:MAX:0.5:8640:600
66 This RRD collects data every 10 seconds and stores its averages over 5
67 minutes, 15 minutes, 1 hour, and 1 day, as well as the maxima for 1
68 hour and 1 day.
70 Consider now that you want to fetch the 15 minute average data for the
71 last hour. You might try
73 rrdtool fetch subdata.rrd AVERAGE -r 900 -s -1h
76 the 15 minute RRA. Therefore, the highest resolution RRA, i.e. 5 minute
77 averages, will be chosen which in this case is not what you want.
79 Hence, make sure that
81 1. both start and end time are a multiple of 900
83 2. both start and end time are within the desired RRA
85 So, if time now is called "t", do
87 end time == int(t/900)*900,
88 start time == end time - 1hour,
89 resolution == 900.
91 Using the bash shell, this could look be:
93 TIME=$(date +%s)
94 RRDRES=900
95 rrdtool fetch subdata.rrd AVERAGE -r $RRDRES \
96 -e $(($TIME/$RRDRES*$RRDRES)) -s e-1h
98 Or in Perl:
100 perl -e '$ctime = time; $rrdres = 900; \
101 system "rrdtool fetch subdata.rrd AVERAGE \
102 -r $rrdres -e @{[int($ctime/$rrdres)*$rrdres]} -s e-1h"'
104 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
106 Apart from the traditional _\bS_\be_\bc_\bo_\bn_\bd_\bs _\bs_\bi_\bn_\bc_\be _\be_\bp_\bo_\bc_\bh, RRDtool does also
107 understand at-style time specification. The specification is called
109 ways to specify time to run your job at a certain date and time. The
110 at-style specification consists of two parts: the T\bTI\bIM\bME\bE R\bRE\bEF\bFE\bER\bRE\bEN\bNC\bCE\bE speci-
113 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
115 The time reference specification is used, well, to establish a refer-
116 ence moment in time (to which the time offset is then applied to). When
118 own part, time reference consists of a _\bt_\bi_\bm_\be_\b-_\bo_\bf_\b-_\bd_\ba_\by reference (which
121 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
123 day are understood as well, including m\bmi\bid\bdn\bni\big\bgh\bht\bt (00:00), n\bno\boo\bon\bn (12:00)
126 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
128 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,
129 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
130 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.
133 single-number date is interpreted as MMDD[YY]YY.
135 _\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
136 as well.
138 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-
142 rrdgraph).
144 Month and day of the week names can be used in their naturally abbrevi-
145 ated form (e.g., Dec for December, Sun for Sunday, etc.). The words
150 The time offset specification is used to add/subtract certain time
153 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.
154 These units can be used in singular or plural form, and abbreviated
155 naturally or to a single letter (e.g. +3days, -1wk, -3y). Several time
156 units can be combined (e.g., -5mon1w2d) or concatenated (e.g., -5h45min
157 = -5h-45min = -6h+15min = -7h+1h30m-15min, etc.)
160 will end with the time offset that may vary depending on your time ref-
161 erence, because all those time units have no single well defined time
162 interval value (1 year contains either 365 or 366 days, 1 month is 28
163 to 31 days long, and even 1 day may be not equal to 24 hours twice a
164 year, when DST-related clock adjustments take place). To cope with
165 this, when you use days, weeks, months, or years as your time offset
166 units your time reference date is adjusted accordingly without too much
168 will take care of this later). This may lead to some surprising (or
169 even invalid!) results, e.g. 'May 31 -1month' = 'Apr 31' (meaningless)
171 Mar 29 1999 -1 day' yields '3:30am Mar 28 1999' (Sunday) which is an
172 invalid time/date combination (because of 3am -> 4am DST forward clock
173 adjustment, see the below example).
175 In contrast, hours, minutes, and seconds are well defined time inter-
176 vals, and these are guaranteed to always produce time offsets exactly
177 as specified (e.g. for EET timezone, '8:00 Mar 27 1999 +2 days' =
178 '8:00 Mar 29 1999', but since there is 1-hour DST forward clock adjust-
179 ment that occurs around 3:00 Mar 28 1999, the actual time interval
180 between 8:00 Mar 27 1999 and 8:00 Mar 29 1999 equals 47 hours; on the
181 other hand, '8:00 Mar 27 1999 +48 hours' = '9:00 Mar 29 1999', as
182 expected)
184 _\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.
185 To disambiguate them, the parser tries to read your mind :) by applying
186 the following two heuristics:
188 1 If m\bm is used in context of (i.e. right after the) years, months,
190 hours, minutes, and seconds it means minutes. (e.g., in -1y6m or
195 is guessed from the number it directly follows. Currently, if the
196 number's absolute value is below 25 it is assumed that m\bm means
197 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-
198 utes, while +24m == +24 months)
200 _\bF_\bi_\bn_\ba_\bl _\bN_\bO_\bT_\bE_\bS: Time specification is case-insensitive. Whitespace can be
201 inserted freely or omitted altogether. There are, however, cases when
202 whitespace is required (e.g., 'midnight Thu'). In this case you should
203 either quote the whole phrase to prevent it from being taken apart by
204 your shell or use '_' (underscore) or ',' (comma) which also count as
205 whitespace (e.g., midnight_Thu or midnight,Thu).
207 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
211 _\b-_\b1_\bm_\bo_\bn_\bt_\bh or _\b-_\b1_\bm -- current time of day, only a month before (may yield
212 surprises, see NOTE3 above).
214 _\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
219 _\b1_\b2_\b/_\b3_\b1_\b/_\b9_\b9 _\b1_\b1_\b:_\b5_\b9_\bp_\bm -- 1 minute to the year 2000 for imperialists.
223 _\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
224 time specification).
226 _\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
227 time specification).
230 as well).
232 _\b1_\b9_\b9_\b7_\b0_\b7_\b0_\b3 _\b1_\b2_\b:_\b4_\b5 -- 12:45 July 3th, 1997 (my favorite, and its even got
233 an ISO number (8601)).
236 The following environment variables may be used to change the behavior
237 of "rrdtool fetch":
240 If this environment variable is set it will have the same effect as
241 specifying the "--daemon" option on the command line. If both are
242 present, the command line argument takes precedence.
245 Tobias Oetiker <tobi@oetiker.ch>
249 1.3.99909060808 2008-09-25 RRDFETCH(1)