[mrtg] adding a ten year RRA

[Stuart Kendrick]

hi,

i'd like to add a ten year RRA to my MRTG installation.

has anyone done this?  i'm wanting a sanity check on the changes i'm 
planning to make ... 

the relevant section from mrtg (i'm simplifying a bit):

my $interval = $$cfg{interval} || 5; 
my $rows = $$rcfg{'rrdrowcount'}{$router} || ( 4000 / $interval);

# [for my environment, $interval = 5 and $rows = 4000/5, i.e. 800]

my @args = ($dotrrd, '-b', $time-10, '-s', int($interval * 60),
                         "RRA:AVERAGE:0.5:1:$rows",
                         "RRA:AVERAGE:0.5:".int(120/$interval).":800",
                         "RRA:AVERAGE:0.5:".int(1440/$interval).":800",

or, to convert to numbers:

1 * 5 minutes = 5 minutes
24 * 5 minutes = 120 minutes (2 hours)
288 * 5 minutes = 1440 minutes (24 hours)

RRA:AVERAGE:0.5:1:800     # 800 rows of 5 minute data ... ~66 hours
RRA:AVERAGE:0.5:24:800    # 800 rows of 2 hour data ... ~66 days 
RRA:AVERAGE:0.5:288:800   # 800 rows of 24 hour data ... 800 days



i figure that all i need to do is to add:

1314 * 5 = 6570 minutes (4.5625 days)

RRA:AVERAGE:0.5:1314:800  # 800 rows of ~4.5 days ... 3650 days

                         "RRA:AVERAGE:0.5:".int(6570/$interval).":800",


and of course do the same for the RRA:MAX line as well


so, by adding two lines, i think i can tell mrtg to create and update an
RRD which is averaging and maxing data across 10 years ...


and then ... all i would have to do is to modify mrtg-rrd.cgi to display
the ten year (or perhaps a five year) graph ...


i'm figuring that this addition will inflict only a small processing and
disk io hit ... after all, rrdtool only updates this aspect of the RRD 
every ~4.5 days.


can anyone foresee a problem with my modifying mrtg this way?


--sk

stuart kendrick
fhcrc

--
Unsubscribe mailto:mrtg-request at list.ee.ethz.ch?subject=unsubscribe
Archive     http://www.ee.ethz.ch/~slist/mrtg
FAQ         http://faq.mrtg.org    Homepage     http://www.mrtg.org
WebAdmin    http://www.ee.ethz.ch/~slist/lsg2.cgi