Hmm.

You can open the graph URL in a separate tab and add &debug=1 at the end to perhaps get some more information.

The device_bits format builds a list of ports and then passes it to the type generic_multi_separated which doesn’t check if the rrd exists.

The list of rrds used is generated in the device_bits type, so it’s difficult to guess what’s going on here.

Adam.

From: McGregor, Kevin <KMcGregor@winnipeg.ca>
Sent: 21 October 2020 14:02
To: Adam Armstrong <adama@observium.org>; 'Observium' <observium@observium.org>
Subject: RE: [Observium] Error drawing graph (can not parse an empty rpn expression)

The .rrd files exist in the same directory as all of the other rrds for that host, and they have the same permissions as all of the others, and they are updated (as evidenced by the rrd file timestamp) every five minutes.

Is there a way to verify the rrd files in some way? Or just blow these two away and recreate them?

Kevin McGregor

From: Adam Armstrong <adama@observium.org>
Sent: October 20, 2020 14:02
To: 'Observium' <observium@observium.org>
Subject: Re: [Observium] Error drawing graph (can not parse an empty rpn expression)

This rrd definition doesn’t actually use any rrds, which suggests the rrds don’t exist.

Adam.

From: observium <observium-bounces@observium.org> On Behalf Of McGregor, Kevin via observium
Sent: 20 October 2020 19:55
To: observium@observium.org
Cc: McGregor, Kevin <KMcGregor@winnipeg.ca>
Subject: [Observium] Error drawing graph (can not parse an empty rpn expression)

I just upgraded from 19.8 to 20.9 CE. In both I’ve been having the same problem: Everything works as expected, except two devices (of 19) produce a big pink box instead of a chart for the “Ports” widget on the Overview page for the devices. The chart is titled “Error Drawing Graph”. Other similar devices (same OS version, etc.) all show a normal-looking chart in the same place. The devices are “SunOS <hostname> 5.11 11.4.25.75.3 sun4v”. Most other devices of the same version work, just not two of them.

When I click on the chart, I get the Ports page and a bigger version of the same chart. Selecting “RRD Command” produces this below the pink box:

Description

Device total traffic in bits/sec.

Performance & Output

RRDTool Output: ERROR: can not parse an empty rpn expression

RRDtool Runtime: 0.011s | Total time: 0.012s

RRDTool Command

/usr/bin/rrdtool graph /tmp/DZSTkOrAZmZQeckq.png -g -Y --alt-autoscale --rigid --start 1603133061 --end 1603219461 --width 1152 --height 300 -c BACK#EEEEEE00 -c SHADEA#EEEEEE00 -c SHADEB#EEEEEE00 -c FONT#000000 -c CANVAS#FFFFFF00 -c GRID#a5a5a5 -c MGRID#FF9999 -c FRAME#5e5e5e -c ARROW#5e5e5e -R normal --font LEGEND:8:'DroidSansMono,DejaVuSansMono' --font AXIS:7:'DroidSansMono,DejaVuSansMono' --font-render-mode normal -E CDEF:inB= CDEF:outB= CDEF:octets=inB,outB,+ CDEF:doutB=outB,-1,* CDEF:inbits=inB,8,* CDEF:outbits=outB,8,* CDEF:bits=inbits,outbits,+ CDEF:doutbits=doutB,8,* VDEF:95thin=inbits,95,PERCENT VDEF:95thout=outbits,95,PERCENT CDEF:pout_tmp=doutbits,-1,* VDEF:dpout_tmp=pout_tmp,95,PERCENT CDEF:dpout_tmp2=doutbits,doutbits,-,dpout_tmp,-1,*,+ VDEF:d95thout=dpout_tmp2,FIRST VDEF:totin=inB,TOTAL VDEF:avein=inbits,AVERAGE VDEF:totout=outB,TOTAL VDEF:aveout=outbits,AVERAGE VDEF:tot=octets,TOTAL COMMENT:' \l' HRULE:999999999999999#FFFFFF:'Total Rx' GPRINT:inbits:LAST:%6.2lf%s GPRINT:inbits:AVERAGE:%6.2lf%s GPRINT:inbits:MIN:%6.2lf%s GPRINT:inbits:MAX:%6.2lf%s GPRINT:totin:%6.2lf%sB COMMENT:'\l' HRULE:999999999999999#FFFFFF:' Tx' GPRINT:outbits:LAST:%6.2lf%s GPRINT:outbits:AVERAGE:%6.2lf%s GPRINT:outbits:MIN:%6.2lf%s GPRINT:outbits:MAX:%6.2lf%s GPRINT:totout:%6.2lf%sB COMMENT:'\l' HRULE:999999999999999#FFFFFF:' Agg' GPRINT:bits:LAST:%6.2lf%s GPRINT:bits:AVERAGE:%6.2lf%s GPRINT:bits:MIN:%6.2lf%s GPRINT:bits:MAX:%6.2lf%s GPRINT:tot:%6.2lf%sB COMMENT:'\l' HRULE:0#999999

RRDTool Files Used

/opt/observium/rrd/<hostname>/port-2.rrd

/opt/observium/rrd/<hostname>/port-1.rrd

Would someone please give me a place to start looking for the problem?

Thanks!