Партнёры:
Хостинг:
rrdtool fetch - fetch data from an rrd.
rrdtool create subdata.rrd -s 10 DS:ds0:GAUGE:300:0:U \ RRA:AVERAGE:0.5:30:3600 \ RRA:AVERAGE:0.5:90:1200 \ RRA:AVERAGE:0.5:360:1200 \ RRA:MAX:0.5:360:1200 \ RRA:AVERAGE:0.5:8640:600 \ RRA:MAX:0.5:8640:600
This RRD collects data every 10 seconds and stores its averages over 5 minutes, 15 minutes, 1 hour and 1 day as well as the maxima for 1 hour and 1 day.
Consider now that you want too fetch the 15 minute average data for last hour. So you might try
rrdtool fetch subdata.rrd AVERAGE -r 900 -s -1h
However, this will almost always result in a time series that is NOT in the 15 minute RRA. Therefore the highest resolution RRA, i.e. 5 minute averages, will be chosen which, in this case, is not what you want.
Hence, make sure that
So, if time now is called ``t'',
do end time == int(t/900)*900, start time == end time -1hour, resolution == 900.
In e.g. bash this could look as:
TIME=$(date +%s); RRDRES=900; rrdtool fetch subdata.rrd AVERAGE -r $RRDRES \ -e $(echo $(($TIME/$RRDRES*$RRDRES))) -s e-1h
Or in perl:
perl -e '$ctime = time; $rrdres = 900; system "rrdtool fetch subdata.rrd AVERAGE \
-r $rrdres -e @{[int($ctime/$rrdres)*$rrdres]} -s e-1h"'
Time-of-day can be specified as HH:MM, HH.MM, or just HH, you can suffix it with am or pm or use 24-hours clock. The few special times of day are understood as well, these include midnight (00:00), noon (12:00) and British teatime (16:00).
The day can be specified as month-name day-of-the-month and optional 2- or 4-digit year number (e.g. March 8 1999). Alternatively, you can use day-of-week-name (e.g. Monday), or one of the words: yesterday, today, tomorrow. You can also specify day as a full date in several numerical formats; these include: MM/DD/[YY]YY, DD.MM.[YY]YY, YYYYMMDD.
NOTE1: this is different from the original at(1) behavior, which interprets a single-number date as MMDD[YY]YY.
NOTE2: if you specify day this way, the time-of-day is REQUIRED to be present.
Finally, you can use words now, start, or end as your time reference. Now refers to the current moment (and is also a default time reference). Start (end) can be used to specify time relative to the start (end) time for those tools that use these categories (rrdfetch, rrdgraph).
Month and weekday names can be used in their naturally abbreviated form (e.g., Dec for December, Sun for Sunday, etc.). The words now, start, end can be abbreviated to n, s, e.
NOTE3: If you specify time offset in days, weeks, months, or years, you will end with the time offset that may vary depending on you time reference, because all those time units have no single well defined time interval value (1 year contains either 365 or 366 days, 1 month is 28 to 31 days long, and even 1 day may be not equal to 24 hours twice a year, when DST-related clock adjustments take place). To cope with this, when you use days, weeks, months, or years as your time offset units your time reference date is adjusted accordingly without taking too much further effort to ensure anything about it (in the hope that mktime(3) will take care of this later). This may lead to some surprising (or even invalid!) results, e.g. 'May 31 -1month' = 'Apr 31' (meaningless) = 'May 1' (after mktime(3) normalization); in the EET timezone '3:30am Mar 29 1999 -1 day' yields '3:30am Mar 28 1999' (Sunday) which is invalid time/date combination (because of 3am -> 4am DST forward clock adjustment, see the below example). On the other hand, hours, minutes, and seconds are well defined time intervals, and these are guaranteed to always produce time offsets exactly as specified (e.g. for EET timezone, '8:00 Mar 27 1999 +2 days' = '8:00 Mar 29 1999', but since there is 1-hour DST forward clock adjustment takes place around 3:00 Mar 28 1999, the actual time interval between 8:00 Mar 27 1999 and 8:00 Mar 29 1999 equals 47 hours; on the other hand, '8:00 Mar 27 1999 +48 hours' = '9:00 Mar 29 1999', as expected)
NOTE4: The single-letter abbreviation for both months and minutes is m. To disambiguate, the parser tries to read your mind :) by applying the following two heuristics:
Final NOTES: Time specification is case-insensitive. Whitespace can be inserted freely or omitted altogether, there are, however, cases when whitespace is required (e.g., 'midnight Thu'). In this case you should either quote the whole phrase to prevent it from being taken apart by your shell or use '_' (underscore) or ',' (comma) which also count as whitespace (e.g., midnight_Thu or midnight,Thu)
-1month or -1m --- current time of day, only a month before (may yield surprises, see the NOTE3 above)
noon yesterday -3hours --- yesterday morning; can be put also as 9am-1day
23:59 31.12.1999 --- 1 minute to the year 2000
12/31/99 11:59pm --- 1 minute to the year 2000 for imperialists
12am 01/01/01 --- start of the new millennium
end-3weeks or e-3w --- 3 weeks before end time (may be used as start time specification)
start+6hours or s+6h --- 6 hours after start time (may be used as end time specification)
931225537 --- 18:45 July 5th, 1999 (yes, seconds since 1970 are valid as well)
19970703 12:45 --- 12:45 July 3th, 1997 (my favorite, and its even got an ISO number (8601))
|
Закладки на сайте Проследить за страницей |
Created 1996-2024 by Maxim Chirkov Добавить, Поддержать, Вебмастеру |