log2rrd

Usage:

log2rrd.pl {mrtg logfile} {destination directory}

Log2rrd is a simple tool for converting MRTG logfiles into round robin
database (RRD) files.  The original version was written last year by
Wrolf Courtney <wrolf@concentric.net> and Russ Wright <wright@LBL.Gov>
with an early test version of RRDTOOL (mrtg-19980526.08).  This
version has been modified to work with the current shared-perl release
of RRD (RRDs).

This script only moves the input/output data averages and does not
make any effort to retain the maximum data rate info that is present
in the mrtg logfiles.  This means that when you request maximum values
for a given time range from your new rrd archive, it will only show
you the averaged max values and not the original data peaks that
occured in the averaged time period.  This may or may not be a problem
at your site.

The conversion script expects 2 arguments - the mrtg logfile to read
and the path for the resulting rrd file.  The script will attempt to
isolate the filename from any path specified for the mrtg input
logfile to create the rrd output file name with the specified
destination directory.  If no destination directory name is included,
the rrd file will be written in the connected directory. 

Note that the resulting rrd DS type is GAUGE.  With a DS type of
counter, rrdupdate will attempt to interpret input data as a counter
value and make a new data average for the specified time interval.
In this case, we need to trick rrdcreate/rrdupdate into letting us
input the data values directly because mrtg had already consolidated
the counter data.  The script contains lines of code that can be
uncommented to allow log2rrd to automatically call rrdtune to change
the resulting file to use the COUNTER data type after the mrtg
logfiles have been read in.  Since not all mrtg data files are counter
data, I leave this option up to the user as to whether to convert
later by hand with rrdtune or let log2rrd perform the task.

Considerations for filenames and converting large numbers of files:

At my own site, I have over 40 Cisco 75xx routers with lots of
interfaces being monitored per router plus about 60 Cisco 5300
terminal servers.  Running log2rrd for each interface individually
would be a very painful process.  Since I am in the process of moving
all of my mrtg datasets over to Cricket, I hacked a separate version
of log2rrd that had more specific file name conversion code to match
my Cricket target names.  This version of log2rrd was called up by
another script that looped through an entire mrtg workdir and
converted all logfiles present in that directory.  This code was far
too specific to my site's version of mrtg logfile names and desired
Cricket target info to be included here.  It would not be a difficult
task to wrap this log2rrd script in a similar fashion tailored to your
own needs.  If you have 100's or 1000's of logfiles to move, the
effort is well worthwhile.

Alan Lichty
Internetworking Planner
Electric Lightwave, Inc.
(360)816-4167