[rrd-users] Beginner RRDTool question

Alex van den Bogaerdt alex at ergens.op.het.net
Sun Mar 9 22:19:39 CET 2008

On Sun, Mar 09, 2008 at 08:09:03PM +0000, Sam Crawford wrote:
> Evening all,
> I'm trying to use RRDTool for a network monitoring application I'm receiving
> data from. The application gives me a bytes/sec reading for active hosts
> every 5 minutes (note: not all hosts, only active ones).
> My problem is that I might receive a burst of data for one interval and then
> nothing else for a long time. However, I still want the rrd to record and
> graph it. But I can't seem to get this working!

RRDtool is not about numbers, it's about rates during an interval.

Don't look at just one update. Always look at two consecutive updates.
You will be asking RRDtool to set a rate, valid for the entire interval
between the two timestamps.

Howver, if your updates are too far apart (where too far is defined by
heartbeat) the rate becomes unknown.

Solution for you:

Always update every five minutes. If you did not get a rate from your
device, update using "U" instead of a number.

Alex van den Bogaerdt

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