# [rrd-users] Re: Calculating percentages over time

tallen at csc.sctboces.org tallen at csc.sctboces.org
Fri Nov 1 18:31:15 MET 2002

```I'm sorry I'm confusing you.  I'm not sure how to make this any simpler.
I have 9 customers.  I have a 14 Mb pipe to the internet.  Over a 24 hour
period, 2 of my customers averaged 0.33Mb/s.  The total (all 9
customers) average was 1.68 Mb/s.  These are school districts so there is very little traffic at
night.  One of these 2 customers had some traffic at night.  This customer
shows 26.7% utilization.  The customer with no night time traffic shows
17.0%.  Two very different results using the same bandwidth over the
same 24 hour period!  The CDEF
calculating the percentage is just cust Mbs divided by total Mbps.  The
answer I want to get is .33/1.68 or about 19.6%.  It's easily done with
GPRINT taking the average of the Mbps and then dividing with the amounts
given with GPRINT by hand after I get the graph, but is there a way to use
the GPRINT averages to do the division on the fly?

Taking the verages of 2 numbers and dividing every five minutes is very
different (or it can be) from taking the average of all of my points for 2
numbers and then dividing.  I want to do the latter.

<More below)

On Thu, 31 Oct 2002, Alex van den Bogaerdt wrote:

>
> On Thu, Oct 31, 2002 at 11:23:37AM -0500, tallen at csc.sctboces.org wrote:
>
> > > So, if that's not your problem, what problem *do* you try to solve?
> >
> > That is the problem.  I need to get the averages of total used and
> > customer used, then do the math.  If I do it with a CDEF, the night-time
> > traffic weighs in way to much.  I don't want to charge a customer for 100%
> > of 14 mb/s if they use 1k/s, I just want to charge for 1k/s.
>
> You're not making sense.  This confuses me and I think it even confuses
> yourself.
>
> First you say the customer is the only one producing traffic.  I respond
> that in such a case it is perfectly OK to show 100% usage.
>
> *Then* you come up with *other* traffic.
>
> > If you're
> > saying I can get the averages over the span of the graph and do tne math
> > with a CDEF, please tell me how.
>
> I cannot tell you how to do it if I don't know what you're trying to do.
> Obviously you don't want to calculate a 1:14000 ratio (1k out of 14M)
> because you rejected this ratio.
>
> If you try to say you want to monitor the amount of bytes sent then do a
> search on the archived list content.  It has been discussed many times.
>
> While you're there, do read the archive.  There's plenty of usefull info
> not only from me but also from others. Not only covering this subject but
> also many other subjects you want to know.

I spent a week searching this archive and the flowscan archive.  No one
has noticed that the percent_of_total_used_over_time:AVERAGE is different
from cust1_over_time:AVERAGE/total_used_over_time:AVERAGE.
Alex, if you'd like, I'll send you this graph.  I've thought about trying
to do % of total available instead.  This would accurately produce results
over the 24 hour period. But I need to divide my costs between the 9
customers (we are non-profit, and our schhol districts decided they want
to be billed by how much they use), so I end up with average % of 14 mb/s
for each customer,
average total % of 14 mb/s, and still I know of no way to do the final
math of the cust%:AVERAGE / total%AVERAGE to do my billing.

Thanks for listening,

Tom

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