[rrd-users] Re: TOTAL CF or determine step

Alex van den Bogaerdt alex at ergens.op.het.net
Thu Mar 11 02:31:30 MET 2004

On Wed, Mar 10, 2004 at 06:08:25PM +0100, Bart Duchesne wrote:

> The only thing I specify is --start --end with the correct timestamps to 
> draw a day,week,month,year graph.

You know the amount of time (s).  You know the average items per second (x/s).

Basic math:  for any s not equal to zero:  (x/s)*s = x

10 items per second (on average) for 20 seconds?  That will be 200 items in
those 20 seconds.

The step size, the number of steps per PDP, the number of PDPs per CDP: all
of these are irrelevant just as long as you _know_ (not: guess) the amount
of seconds.

In order to be able to know the amount of seconds, you need to be sure
about the start and end times.  To be sure of those, you need to know
the boundaries and thus you need to know, when calling rrdtool, what the
properties of each RRA are.

By this I mean RRDtool will magically alter your start and end times if
they are not on RRA-boundaries.  Thus you think you know the amount of
time graphed yet your numbers are inaccurate.  By carefully specifying
start and end (or: start and duration, or end and duration) you can avoid
this problem -> you _know_ the interval.

begin  sig
This message was produced without any <iframe tags

Unsubscribe mailto:rrd-users-request at list.ee.ethz.ch?subject=unsubscribe
Help        mailto:rrd-users-request at list.ee.ethz.ch?subject=help
Archive     http://www.ee.ethz.ch/~slist/rrd-users
WebAdmin    http://www.ee.ethz.ch/~slist/lsg2.cgi

More information about the rrd-users mailing list