nanog mailing list archives

Re: PSINet/Cogent Latency


From: Matt Zimmerman <mdz () csh rit edu>
Date: Tue, 23 Jul 2002 09:46:56 -0400


On Mon, Jul 22, 2002 at 10:50:03PM -0700, Doug Clements wrote:

I think the problem with using rrdtool for billing purposes as described
is that data can (and does) get lost. If your poller is a few cycles late,
the burstable bandwidth measured goes up when the poller catches up to the
interface counters. More bursting is bad for %ile (or good if you're
selling it), and the customer won't like the fact that they're getting
charged for artifically high measurements.

RRDtool takes into account the time at which the sample was collected, and
if it does not exactly match the expected sampling period, it is resampled
on the fly.  See:

http://people.ee.ethz.ch/~oetiker/webtools/rrdtool/tutorial/rrdtutorial.html

under "Data Resampling" for more information.

RRDtool has some quirks when used for billing purposes, but it is not guilty
of the error that you describe.

-- 
 - mdz


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