[rrd-users] Question about time stamp, etc with GAUGE DST

[Chris Nighswonger]

On Thu, Nov 8, 2012 at 10:17 PM, Ryan Kubica <kubicaryan at yahoo.com> wrote:

>
> RRD is interpolating the value since you aren't inserting on the
> step-second (1352425140 1352425200 etc...)
>
> Since your insert is part way into the step interval of 1352425140 rrd is
> splitting the value between the two step intervals.
>
>
That's sort of what I thought might be happening.


>  If you don't want interpolation the easiest way to avoid it is to
> subtract the modulus of time of 60 from time: time - (time % 60) ... gives
> you the step interval time to insert with.
>
> ps: you should also ensure that your loop code isn't doing a sleep 60,
> since you will drift in time with logic like that (that 3 seconds you
> gained between 121 and 184) ... use a wait counter that's based on:
> sync_time + 60 and wait until sync_time on each loop, etc.
>
>
So now I'm doing such as this:

sync_time = time -  (time % 60)  ## set sync_time to zero secs

while (1) {
    if (time == sync_time + 60) {  ## has a minute elapsed
        sync_time = time - (time % 60)  ## set current sync_time to zero
secs; use this as the RRD insert time

        #### grab data and record it ####

    }
}

So far the calculated time field is dead on the RRD time field.

Thanks!

Kind Regards,
Chris
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