[rrd-users] Gigabytes of logs: "libpng error: stream error"

Daniellek daniel at fenert.net
Tue Apr 8 15:05:10 MEST 2003

I use cacti with rrdtool for accounting, and from time to time
there's a storm of apache logs like this in a subject
(this line is written till 2GB limit of log size is met).

Today I caught it in the middle, on these are the results:
rrdtool (1.0.41) takes all the cpu availible, and strace 
	# strace -p 20880
	write(2, "libpng error: stream error\n", 27) = -1 EPIPE (Broken pipe)
	--- SIGPIPE (Broken pipe) ---
and...exits, it looks like there is one SIGPIPE after another...
After killing (-9 only kills it) rrdtool, log flood to error_log
Beggining of error_log looks like this:
libpng error: Write Error
libpng error: stream error
libpng error: stream error
libpng error: stream error

... and 2GB of identical lines.

Then I found that this time, I can reproduce situation, it is caused
(this time, I'm not sure if past error-floods where caused by the same)
by switching Graph Output Preview in Edit Graph Items in Cacti. 
Rrdtool source for this graph is:

/usr/local/rrdtool/bin/rrdtool graph - \
--imgformat=PNG \
--start="-86400" \
--title="Traffic Analysis for Peer" \
--rigid \
--base=1000 \
--height=400 \
--width=700 \
--upper-limit=2306867 \
--lower-limit=-2306867 \
--vertical-label="Bits Per Second" \
DEF:a="/home/www/cacti/rra/traf_4_in.rrd":traf_:AVERADEF:b="/home/www/cacti/rra/traf_4_out.rrd":traf_:AVERCDEF:cdefa=a,-8,* \
CDEF:cdefc=a,8,* \
CDEF:cdeff=b,8,* \
AREA:cdefa#00CF00:"Inbound" \
HRULE:-2097152#FF4105:"MAX Inbound 2Mbit/s\n" \
GPRINT:cdefc:LAST:" Current\:%8.2lf %s" \
GPRINT:cdefc:AVERAGE:"Average\:%8.2lf %s" \
GPRINT:cdefc:MAX:"Maximum\:%8.2lf %s" \
AREA:cdeff#F51D30:"Outbound" \
GPRINT:cdeff:LAST:"Current\:%8.2lf %s" \
HRULE:0#000000:"" \
GPRINT:cdeff:AVERAGE:"Average\:%8.2lf %s" \
HRULE:2097152#FF4105:"Max Outbound 2Mbit/s" \
GPRINT:cdeff:MAX:"Maximum\:%8.2lf %s"

Does anyone know what's wrong?

Additional inforamtion, it's on Slackware 8.1 with 2.4.20 kernel.

Daniel Fenert                 --==> daniel at fenert.net <==--
==-P o w e r e d--b y--S l a c k w a r e-=-ICQ #37739641-==
=======- http://daniel.fenert.net/ -=======< +48604628083 >

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