[rrd-users] weird behaviour of rrd graph

[Roland Kletzing]

Hello,

thanks for the hints!

> yes, that is the 'old' solution ... and it does work. but since
> rrdtool is not even looking at coverage at the future end of the
> range this does not matter any more ...

that refers to actual versions of rrdtool!?
unfortunately i`m locked to 1.2.23 , as i don`t have a clue how to get
a more recent version for that platform. maybe i can update to 1.2.30
by switching to more recent openWRT build.  (which is embedded linux
for routers). Would that help,too?

Anyway, regarding the modulo trick - i`m not sure if i got that right

You mean like this ?

export now=$(( `date +"%s"` - $((`date +"%s"` % 21600)) ))
rrdtool .... --start end-1y  --end $now ....

(i`m using busybox date, where date +"%s" means seconds since epoch.)

regards
Roland


--------------------------------------------------
From: "Tobias Oetiker" <tobi at oetiker.ch>
Sent: Tuesday, September 28, 2010 11:12 PM
To: "Alex van den Bogaerdt" <alex at vandenbogaerdt.nl>
Cc: <rrd-users at lists.oetiker.ch>
Subject: Re: [rrd-users] weird behaviour of rrd graph

> Today Alex van den Bogaerdt wrote:
>
>> > also note that recent rrdtool versions have become more 'stable' in
>> > their choices ... by only looking to the past and not to the
>> > present since all RRAs by definition cover the present to the best
>> > of their abilities ...
>>
>>
>> I'm not sure, but isn't this the same difference?
>>
>> now-1y will still sometimes be exactly on one RRA boundary, but usually 
>> not.
>> Just as now does.
>>
>> I suggest Roland tries to compute current_time - (current_time modulo 
>> 21600)
>> and use that instead of  "now" to see if that makes a difference. I'm not
>> going to bet on it, but it would sure be my first try.
>>
>> 2nd and 3rd try would be 262800 and 2628000 where I wrote 21600.
>
> yes, that is the 'old' solution ... and it does work. but since
> rrdtool is not even looking at coverage at the future end of the
> range this does not matter any more ...
>
> cheers
> tobi
>
>>
>>
>>
>
> -- 
> Tobi Oetiker, OETIKER+PARTNER AG, Aarweg 15 CH-4600 Olten, Switzerland
> http://it.oetiker.ch tobi at oetiker.ch ++41 62 775 9902 / sb: -9900
>
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