[rrd-users] recover from logged incorrect time

William Owen William.Owen at profilesmail.com
Sat Apr 28 15:39:33 CEST 2007

I'm running in a MS environment but had a similar issue with a
collection box at a remote site.  I ended up creating a VBScript wrapper
that verified the local time against a known good time server.  Instead
of scheduling my data collector to run, I scheduled the wrapper.  If the
time wasn't within x-minutes of accurate (10 in my case), my collection
script would not be called, data collection is skipped that cycle and a
forced time sync is initiated.  I'm sure a similar logic could be
applied to whatever OS you are running on your embedded system.

This is a "lesser of two evils" issue.  Can you live without a polling
cycle here and there or is it worse to have large inaccurate gaps that
cause resolution loss if you fix them?

-----Original Message-----
From: rrd-users-bounces at lists.oetiker.ch
[mailto:rrd-users-bounces at lists.oetiker.ch] On Behalf Of Tobias Oetiker
Sent: Saturday, April 28, 2007 4:40 AM
To: Rob Conway
Cc: rrd-users at lists.oetiker.ch
Subject: Re: [rrd-users] recover from logged incorrect time

Hi Rob,

you can 'dump' and edit the xml to 'reset' the time ... but note,
that an rrdtool update is a rather complex operation, so reverting
it is equaly complex and always coupled with some loss of data ...

better is to first make sure your time is right ...


Today Rob Conway wrote:

> I ahve a small emmbedded processor running rrdtools.  When the unit
starts up the time is incorrect and I have on a number of occasions had
the system log data with a time stamp that is 10hrs in front of real
time.  When the clock is corrected rrd will not accept the data until
the time stamp is greater than the last logged.  Anyway of somehow
forcing acceptance or deletion of last value that was logged.
> cheers  rob

Tobi Oetiker, OETIKER+PARTNER AG, Aarweg 15 CH-4600 Olten
http://it.oetiker.ch tobi at oetiker.ch ++41 62 213 9902

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