[rrd-users] rrd problem
linux at thehobsons.co.uk
Mon Apr 26 17:59:59 CEST 2010
>I create a rrd, the info is as follows:
>filename = "mailrelay1.rrd"
>rrd_version = "0003"
>step = 300
>last_update = 1272293941
>as you can see the step is 300 seconds, and I update the rrd every minute,
>but I get NaN when I "fetch" from the rrd
How long did you enter data for ?
Which RRA did you fetch ?
Each data point (where primary or consolidated) will not be available
until there has been atr least one update after the period ends. For
a primary data point, this will be after an integral number of "step"
seconds from unix epoch has elapsed - so that means every 5 minutes
(ie n:00, n:05, n:10, ...). For consolidated data points, it means
integral multiples of (step*pdp_per_row) from unix epoch (eg if
pdp_per_row were 3, then that would mean on the hour, quarter past,
half past, and quarter to). In your case, pdp_per_row is 1 so you
should get data available when you do an update that is on or past
each five minute step.
Ie, if you update at 00:04:59 then you have not completed the step
and it will be NaN. If you update on or after 00:05:00 then it is and
data will be available for that step.
In each case, you must have entered enough data for the sample period
to be known. In your case, if you don't enter data for more than 10
minutes (600s) then the data becomes unknown.
In your dump, I see unknown_sec = 241 - that suggests you've only
just started entering data - give it another 5 minutes and it should
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