=head1 NAME

mrtg-logfile - description of the mrtg-2 logfile format

=head1 SYNOPSIS

This document provides a description of the contents of
the mrtg-2 logfile.

=head1 OVERVIEW

The logfile consists of two main sections. 

=over

=item The first Line

It stores the traffic counters from the most recent run of mrtg.

=item The rest of the File

Stores past traffic rate averates and maxima at increassing
intervals.

=back

The first number on each line is a unix time stamp. It represents
the number of seconds since 1970.

=head1 DETAILS

=head2 The first Line

The first line has 3 numbers which are:

=over

=item A (1st column)

A timestamp of when MRTG last ran for this interface.  The timestamp is the
number of non-skip seconds passed since the standard UNIX "epoch" of midnight
on 1st of January 1970 GMT.

=item B (2nd column)

The "incoming bytes counter" value.

=item C (3rd column)

The "outgoing bytes counter" value.

=back

=head2 The rest of the File

The second and remaining lines of the file contains 5 numbers
which are:

=over

=item A (1st column)

The Unix timestamp for the point in time the data on this line is relevant.
Note that the interval between timestamps increases as you prograss through the
file. At first it is 5 minutes and at the end it is one day between two lines.

This timestamp may be converted in OpenOffice Calc or MS Excel by using the
following formula

 =(x+y)/86400+DATE(1970;1;1)

(instead of ";" it may be that you have to use "," this depends on the context and your locale settings)

you can also ask perl to help by typing

 perl -e 'print scalar localtime(x),"\n"'

B<x> is the unix timestamp and B<y> is the offset in seconds
from UTC. (Perl knows B<y>).


=item B (2nd column)

The average incoming transfer rate in bytes per second. This is valid
for the time between the A value of the current line and the A value of the
previous line.

=item C (3rd column)

The average outgoing transfer rate in bytes per second since the previous
measurement.

=item D (4th column)

The maximum incoming transfer rate in bytes per second for the current
interval. This is calculated from all the updates which have occured in the
current interval. If the current interval is 1 hour, and updates have
occured every 5 minutes, it will be the biggest 5 minute transfer rate seen
during the hour.

=item E (5th column)

The maximum outgoing transfer rate in bytes per second for the current interval.

=back

=head1 AUTHOR

Butch Kemper E<lt>kemper@bihs.netE<gt> and
Tobias Oetiker E<lt>oetiker@ee.ethz.chE<gt> 
