[rrd-users] Average calculations for working hours only, but 7x24 stored
ralf-buero at kruedewagen.de
Sat Nov 12 10:03:46 MET 2005
how I can calculate an average depending on time (time of day, day) ? For
example calculating the average only of working hours. But let's explain me a
Let's say I have a RRDtool database containing a single DS "response_time". I
collect data every 15 minutes and store it to the database. I do that 7x24
hours every day of a year. I can easily calculate the average of the response
time for a day, a week, a month or a year. So far, so good.
My boss wants now to get an average (day, week, month, year) of the same DS,
but in addition to 7x24 also within working hours from Monday to Friday
between 09:00 and 17:00.
My alternatives / ideas:
1) I could store a second DS "response_time_wh" to the same database. I would
then update the 1st DS every time but the 2nd DS only within these working
Disadvantage: I need to know in advance which time I need to start and stop
(working hours) filling the 2nd DS. That's not flexible, since the working
hour could not be changed to 08:00 afterwards.
2) Is there any tricky RPN expression to do that, maybe embedded in a small
script for matching day of a week and hours to UNIX timestamps ?
Advantage: Filter expression can be changed later. Interactive calculations
possible (web form). And, I could also filter out time ranges which are
defined as "scheduled downtime".
>From RPN tutorial I know that it is possible to define something for a single
timeframe. But for a monthly average I need to filter out a lot of "unwanted"
time ranges. With SQL this would be no problem, but with RRDtool I have my
Any idea on how to go for alternative No. 2 ?
Best Regards and thanks for your help in advance
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