[mrtg] resetting graphs periodically (i.e. monthly)

[Steve Shipway]

> I want to "gauge" (pun intended) various usages on a month-to-month
> basis.
...
> I am graphing this with a "gauge" so that I can see it's growth over
> time.  But what I want to be able to do however is "reset" graph at
> intervals, like say monthly, so that at the start of every month, the
> graph starts at 0 and grows until the end of the month.
> 
> I would prefer not to sacrifice the historical data however and just
> trash the .log every month (which seems to be one way to achieve this,
> at the expense of the yearly graph, which is why I don't want to trash
> the .log file).
> 
> Am I reaching for something here that mrtg just cannot do?

I would suggest you switch to using MRTG with RRDTool, and not in native (log file) mode.  By doing this, you get a lot more control over what information you can get out of the accumulated data.

If you use MRTG with RRDtool you need a display frontend (as the graphs are only generated on demand).  I'd suggest using Routers2.cgi (but then I'm biased).  By using Routers2, you can enable '95th Percentile Mode' in the routers2.conf, and you will get 95th Percentile calculation, plus Totals on the graphs -- and what you're after is a total on a monthly basis.  You could also enable the Routers2 RRD Archiving and then be able to view the historical data as far back as you like (or as far as you have disk space, anyway).

Alternatively, you can always code something in Perl using the RRD libraries to extract the data from the rrd database and use it however you like.

For more info, see www.rrdtool.og, www.steveshipway.org/software, www.steveshipway.org/book 

Steve