--- Daniel Hartmeier <[EMAIL PROTECTED]> wrote:
> On Thu, Jul 13, 2006 at 11:07:46AM -0400, Peter wrote:
>
> > I have installed the pfstat 1.7 package on my 3.8 system. The
> trouble
> > is that I do not get any data being graphed. Here is my test
> setup:
> >
> > # cat /etc/pf.conf
> > pass log all
>
> Add "set loginterface fxp0", which designates one interface to
> collect
> those counters for, which pfstat collects.
>
> (newer versions of pfstat can query other interface counters, so the
> loginterface isn't needed anymore, and you can plot graphs for
> multiple
> interfaces)
>
> > Bonus question: How does the program reconcile the data file being
> > updated at a different interval than the one the graph is being
> > generated with (i.e. every one minute as opposed to every five
> > minutes)?
>
> Each line contains the timestamp (unix epoch time, seconds since
> 1970)
> of when the counters had those values of that line.
>
> The rest is simple math done by pfstat. When it needs to find out
> which
> height to draw one specific pixel at, it calculates what timestamps
> the
> left and right edge of the pixel represent. For example, if you plot
> a
> whole year on 800 pixels width, one pixel represents about
> 365*24*60*60/800 == 39420 seconds. If this is left-most pixel, and
> you
> plot the year ending with timestamp 1152805255 (today, 17:40:55
> MEST),
> that pixel represents the time range 1152765835-1152805255.
>
> For that pixel, pfstat will take all log entries that fall at least
> partly within that range, and calculates weighted average, minimum,
> and
> maximum of all matching log entries.
>
> While it costs a little CPU time to do that, it allows to plot graphs
> with arbitrary widths over arbitray time ranges, no matter how often
> or
> regular the values are collected. In extreme cases (much more pixels
> than values), you'll see one value spread over many pixels,
> generating a
> "blocky" staircase or even a simple horizontal line. But the average
> should be mathematically correct, i.e. the area below the line (width
> times height) matches the amount of bytes transfered in that time
> period.
>
> Daniel
Thank you Sir.
Peter
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