[mrtg] No data in RRD file, but MRTG runs fine

[Steve Shipway]

The first time you run the data collection, the RRD will store the counters but not the rates as it does not have a previous value (yet).  This is a 'counter' data type so you need TWO successive polls to get a differrence which is divided by the time interval to give a rate.  Rune a poll, then 5min later run another, and you'll get values out.

Steve

________________________________________
From: mrtg-bounces+s.shipway=auckland.ac.nz at lists.oetiker.ch [mrtg-bounces+s.shipway=auckland.ac.nz at lists.oetiker.ch] On Behalf Of Christian Ludwig [cludwig at net.t-labs.tu-berlin.de]
Sent: Saturday, 8 May 2010 2:14 a.m.
...
--snpo: run external  snmp_sum -c public -h localhost -o diskIONWrittenX
--snpo: External result:6687612928 out:6687612928 uptime:localhost name:diskIONWrittenX for localhost
--log: RRDs::tune(/var/www/mrtg/localhost/localhost.diskionwrittenx.rrd -a ds0:1000 -a ds1:1000 -d ds0:COUNTER -d ds1:COUNTER)
--log: RRDs::update(/var/www/mrtg/localhost/localhost.diskionwrittenx.rrd, '1273074602:6687612928:6687612928')
--log:  got: ???/???