[rrd-users] Re: new log2rrd beta - handles MAX values, etc.

[Rainer Bawidamann]

In article <20000626140324.A29146 at doit.wisc.edu>,
	plonka at doit.wisc.edu (Dave Plonka) writes:
>> 
>> You create the rrd files with the rras (steps:rows, MAX/AVERAGE each)
>>        1:600 / 6:600 / 24:600 / 288:600
>> (altough the documentation says 732 rows for the last rra). But the mrtg
>> log files contain older data: The rras of a rrd file overlap (all end
>> "now"), the "rras" of a mrtg log file not (they "append"). I think The
>> Right Sizes (TM) for a mrtg-compatible rrd file is:
>> 
>>        1:600 / 6:700 / 24:775 / 288:797
> 
> I *think* that we want log2rrd to preserve the RRA sizes that store
> exactly the data that the ".log" file contains, not (necessarily) what
> it would create if one initially sets "UseRRDTool Yes".  Which sizes
> are you giving me?

The sizes I use to create rrds which should cover the sizes of log
files (I discussed this with Alex some time ago). mrtg/rateup has

-  ~600 5 minutes smaples  ->  3000 min =  50 h
-  ~600 30 minutes samples -> 18000 min = 300 h
-  ~600 2 hour samples     ->  1200 h
-  ~732 1 day samples      ->   732 d = 17568 h

the first 30 min sample is 5-25 min after the last 5 min sample,
the first 2 hour smaple is after the last 30 min sample ...

so: the  5 min samples are from now-50h    to now
    the 30 min samples are from now-350h   to now-50h
    the 2 hour samples are from now-1550h  to now-350h
    the  1 day samples are from now-19118h to now-1550h

In the rrd file every rra ends "now". So when filling the rrd file with
the values from the log file additional values are entered for the other
rras. I.e. the rrd file contains
     5 min samples from now-50h    to now
    30 min samples from now-350h   to now
    2 hour samples from now-1550h  to now
    1 day samples  from now-19118h to now

So there are 
-  5 min samples for 50h    -> 600 samples
- 30 min samples for 350h   -> 700
- 2 hour smaples for 1550h  -> 775
-  1 day samples for 19118h -> 796 (+14h) -> 797

>> And what about reading a mrtg config file to look for
>> the log files and the datasourcetype? ;-)
> 
> You mean look for the "gauge", "absolute", etc. options...  hmm...

And to get the names of (all) the log files ...

> I might be willing to add this - if it could be done reasonably and
> quickly.

I think it wouldn't take much time (for me). I would take the parser out
of mrtg and add some calls to log2rrd. Maybe I'll do it because it's
good for 14all ;-)

Bye ... Rainer