Subject: Re: rrdtool dumps core
To: NetBSD/pkgsrc users <>
From: Martti Kuparinen <>
List: pkgsrc-users
Date: 10/31/2007 14:17:44
Martti Kuparinen wrote:

> I'm using rrdtool-1.2.23nb1 on several NetBSD servers (i386 3.1.1 and 
> amd64 4.0_RCx) and on all servers I see weird crashes (=core dump) when 
> generating the "last 12 months" image if the time is 03:00 - 04:55.
> During other times (05:00-24:00-02:55) I have no problems at all. Also I 
> have no problems generating the "last 24 hours"/"last 7 days"/"last 4 
> weeks" images even if the time is between 03:00 and 04:55.

After switching from summer time to normal time the core dumps started to appear 
at 02:00 (AM). After some debugging and help from the rrdtool author, the cause 
of this problem was identified :-)

Basically this was EDUMMYUSER (=dummy user error), the RRA statements for my 
"year statistics" were saving history data for 288 years (!) instead of the 
intended period of 1 year and according to the author this crash most likely has 
something to do with time_t overflow. Why this only happens when I'm running 
rrdtool at UTC midnight (or 02:00 in my local time) is still unclear to me...

Anyway, pay attention to your RRA lines and read the man page :-) This is what I 
have now with our 48+2 port HP ProCurve switches (with 5 year of history):

         ${RRDTOOL} create ${1} -s 300                           \
                 DS:i1:COUNTER:600:0:${MAXINT}                   \
                 DS:o1:COUNTER:600:0:${MAXINT}                   \
                 DS:i50:COUNTER:600:0:${MAXINT}                  \
                 DS:o50:COUNTER:600:0:${MAXINT}                  \
                 RRA:AVERAGE:0.5:1:288                           \
                 RRA:MIN:0.5:1:288                               \
                 RRA:MAX:0.5:1:288                               \
                 RRA:AVERAGE:0.5:6:336                           \
                 RRA:MIN:0.5:6:336                               \
                 RRA:MAX:0.5:6:336                               \
                 RRA:AVERAGE:0.5:24:372                          \
                 RRA:MIN:0.5:24:372                              \
                 RRA:MAX:0.5:24:372                              \
                 RRA:AVERAGE:0.5:288:1830                        \
                 RRA:MIN:0.5:288:1830                            \