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
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 Address of the rrdcached daemon. If specified, a "flush"
44 command is sent to the server before reading the RRD files.
46 configured 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
52 In order to get RRDtool to fetch anything other than the finest
54 boundaries that are multiples of the desired resolution. Consider the
55 following example:
57 rrdtool create subdata.rrd -s 10 DS:ds0:GAUGE:300:0:U \
58 RRA:AVERAGE:0.5:30:3600 \
59 RRA:AVERAGE:0.5:90:1200 \
60 RRA:AVERAGE:0.5:360:1200 \
61 RRA:MAX:0.5:360:1200 \
62 RRA:AVERAGE:0.5:8640:600 \
63 RRA:MAX:0.5:8640:600
65 This RRD collects data every 10 seconds and stores its averages over 5
66 minutes, 15 minutes, 1 hour, and 1 day, as well as the maxima for 1
67 hour and 1 day.
69 Consider now that you want to fetch the 15 minute average data for the
70 last hour. You might try
72 rrdtool fetch subdata.rrd AVERAGE -r 900 -s -1h
75 the 15 minute RRA. Therefore, the highest resolution RRA, i.e. 5 minute
76 averages, will be chosen which in this case is not what you want.
78 Hence, make sure that
80 1. both start and end time are a multiple of 900
82 2. both start and end time are within the desired RRA
84 So, if time now is called "t", do
86 end time == int(t/900)*900,
87 start time == end time - 1hour,
88 resolution == 900.
90 Using the bash shell, this could look be:
92 TIME=$(date +%s)
93 RRDRES=900
94 rrdtool fetch subdata.rrd AVERAGE -r $RRDRES \
95 -e $(($TIME/$RRDRES*$RRDRES)) -s e-1h
97 Or in Perl:
99 perl -e '$ctime = time; $rrdres = 900; \
100 system "rrdtool fetch subdata.rrd AVERAGE \
101 -r $rrdres -e @{[int($ctime/$rrdres)*$rrdres]} -s e-1h"'
103 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
104 Apart from the traditional _\bS_\be_\bc_\bo_\bn_\bd_\bs _\bs_\bi_\bn_\bc_\be _\be_\bp_\bo_\bc_\bh, RRDtool does also
105 understand at-style time specification. The specification is called
107 ways to specify time to run your job at a certain date and time. The
108 at-style specification consists of two parts: the T\bTI\bIM\bME\bE R\bRE\bEF\bFE\bER\bRE\bEN\bNC\bCE\bE
111 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
112 The time reference specification is used, well, to establish a
113 reference moment in time (to which the time offset is then applied to).
115 On its own part, time reference consists of a _\bt_\bi_\bm_\be_\b-_\bo_\bf_\b-_\bd_\ba_\by reference
118 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
120 day are understood as well, including m\bmi\bid\bdn\bni\big\bgh\bht\bt (00:00), n\bno\boo\bon\bn (12:00)
123 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
125 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,
126 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
127 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.
130 single-number date is interpreted as MMDD[YY]YY.
132 _\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
133 as well.
138 the start (end) time for those tools that use these categories
141 Month and day of the week names can be used in their naturally
142 abbreviated form (e.g., Dec for December, Sun for Sunday, etc.). The
146 The time offset specification is used to add/subtract certain time
149 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.
150 These units can be used in singular or plural form, and abbreviated
151 naturally or to a single letter (e.g. +3days, -1wk, -3y). Several time
152 units can be combined (e.g., -5mon1w2d) or concatenated (e.g., -5h45min
153 = -5h-45min = -6h+15min = -7h+1h30m-15min, etc.)
156 will end with the time offset that may vary depending on your time
157 reference, because all those time units have no single well defined
158 time interval value (1 year contains either 365 or 366 days, 1 month is
159 28 to 31 days long, and even 1 day may be not equal to 24 hours twice a
160 year, when DST-related clock adjustments take place). To cope with
161 this, when you use days, weeks, months, or years as your time offset
162 units your time reference date is adjusted accordingly without too much
164 will take care of this later). This may lead to some surprising (or
165 even invalid!) results, e.g. 'May 31 -1month' = 'Apr 31' (meaningless)
167 Mar 29 1999 -1 day' yields '3:30am Mar 28 1999' (Sunday) which is an
168 invalid time/date combination (because of 3am -> 4am DST forward clock
169 adjustment, see the below example).
171 In contrast, hours, minutes, and seconds are well defined time
172 intervals, and these are guaranteed to always produce time offsets
173 exactly as specified (e.g. for EET timezone, '8:00 Mar 27 1999 +2 days'
174 = '8:00 Mar 29 1999', but since there is 1-hour DST forward clock
175 adjustment that occurs around 3:00 Mar 28 1999, the actual time
176 interval between 8:00 Mar 27 1999 and 8:00 Mar 29 1999 equals 47 hours;
177 on the other hand, '8:00 Mar 27 1999 +48 hours' = '9:00 Mar 29 1999',
178 as expected)
180 _\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.
181 To disambiguate them, the parser tries to read your mind :) by applying
182 the following two heuristics:
184 1. If m\bm is used in context of (i.e. right after the) years, months,
186 hours, minutes, and seconds it means minutes. (e.g., in -1y6m or
191 is guessed from the number it directly follows. Currently, if the
192 number's absolute value is below 25 it is assumed that m\bm means
193 m\bmo\bon\bnt\bth\bhs\bs, otherwise it is treated as m\bmi\bin\bnu\but\bte\bes\bs. (e.g., -25m == -25
194 minutes, while +24m == +24 months)
196 _\bF_\bi_\bn_\ba_\bl _\bN_\bO_\bT_\bE_\bS: Time specification is case-insensitive. Whitespace can be
197 inserted freely or omitted altogether. There are, however, cases when
198 whitespace is required (e.g., 'midnight Thu'). In this case you should
199 either quote the whole phrase to prevent it from being taken apart by
200 your shell or use '_' (underscore) or ',' (comma) which also count as
201 whitespace (e.g., midnight_Thu or midnight,Thu).
203 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
206 _\b-_\b1_\bm_\bo_\bn_\bt_\bh or _\b-_\b1_\bm -- current time of day, only a month before (may yield
207 surprises, see NOTE3 above).
209 _\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
214 _\b1_\b2_\b/_\b3_\b1_\b/_\b9_\b9 _\b1_\b1_\b:_\b5_\b9_\bp_\bm -- 1 minute to the year 2000 for imperialists.
218 _\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
219 time specification).
221 _\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
222 time specification).
225 as well).
227 _\b1_\b9_\b9_\b7_\b0_\b7_\b0_\b3 _\b1_\b2_\b:_\b4_\b5 -- 12:45 July 3th, 1997 (my favorite, and its even got
228 an ISO number (8601)).
231 The following environment variables may be used to change the behavior
232 of "rrdtool fetch":
235 If this environment variable is set it will have the same effect as
236 specifying the "--daemon" option on the command line. If both are
237 present, the command line argument takes precedence.
240 Tobias Oetiker <tobi@oetiker.ch>
244 1.4.2 2008-09-25 RRDFETCH(1)