[rrd-users] Re: Calculating traffic

Iñaki Martínez sistema at euskal-linux.org
Wed Jun 26 13:48:22 MEST 2002

Kaixo Alex van den Bogaerdt!!!

First of all..... THANK YOU VERY MUCH for your help!!!!!

> >  What does this mean????
>
> What is it you don't understand?  I specifically wrote how to do
> this calculation.

I thought i understand in some way how rrd file works, but i did not
understand at all.

> As a formula:
> total_time = time_per_PDP * amount_of_PDPs_per_CDP * amount_of_CDPs

OK..... a write down....

> >  i thought that with 3725 i will have a five years rrd file.....
>
> There's *no* way I can come up with this number so explain.  While
> you're doing that maybe we can see where you go wrong.

Taken from rrdtool tutorial......
600 samples of 5 minutes  (2 days and 2 hours)
700 samples of 30 minutes (2 days and 2 hours, plus 12.5 days)
775 samples of 2 hours    (above + 50 days)
797 samples of 1 day      (above + 732 days, rounded up to 797)

With this formula:

2261 = 2 + 12 + 50 + 1 + (732 * 3) for three years

> For 5 years worth of data:
>
> 5 years would be 5 * 365 days + two extra = 1827 days.  (The two extra
> days are for february 29th).
>
> 1827 days * 86400 seconds per day = 157852800 seconds.
> The amount of steps in the last PDP is 288.
> The amount of time per PDP is 60
>
> So:
> total_time = time_per_PDP * amount_of_PDPs_per_CDP * amount_of_CDPs
> 157852800  =      60      *  288                   * amount_of_CDPs
>
> 157852800  =      17280                            * amount_of_CDPs
> 157852800/17280 = amount_of_CDPs
> amount_of_CDPs = 9135

To clear:

time_per_PDP           = --step value
amount_of_PDPs_per_CDP = steps (RRA)
amount_of_CDPs         = rows (RRA)

this are OK????

then from the above example (tutorial):

60 * 288 * 797 = 13772160 segs =~ 159 days

but in the tutorial says 732 days

I am confused.......

Then.....
must i change 3725 for 9135.... ?????
must i change all???

Well, i have the following:

rrdtool create port_xxx.rdd --step 60 \
DS:in:COUNTER:600:U:U                 \
DS:out:COUNTER:600:U:U                \
RRA:AVERAGE:0.5:1:600                 \
RRA:AVERAGE:0.5:6:700                 \
RRA:AVERAGE:0.5:24:775                \
RRA:AVERAGE:0.5:288:3725              \
RRA:MAX:0.5:1:1:600                   \
RRA:MAX:0.5:6:700                     \
RRA:MAX:0.5:24:775                    \
RRA:MAX:0.5:288:3725;

what do you change to:

1) have a five years of data
2) make a graph of two hours and see smooth
3) make a graph of a year of 2,3,4 or 5 years ago

Well i think that for now if enough!!!!