How-to debug graphs not being created

Owned by Anastasios Thomaidis
Last updated: Dec 11, 2023 by Matthew Hierholzer
2 min read
Round Robin Database (RRD) error "Cannot get RRD data" and how to troubleshoot.

LAST TESTED ON CHECKMK 2.2.0P1

Table of Contents

Problem

You may be impacted by a Cannot Create Graph error:

Screenshot of CPU utilization service for mysite01. Error reads cannot create graph


To visualize a graph, Checkmk uses RRD. The RRD needs, by nature, two files:

-rw-rw---- 1 mysite mysite      93 Jun  2 07:21 CPU_Utilization_Packet_CPU_2.info
-rw-r--r-- 1 mysite mysite  384952 Jun  2 11:22 CPU_Utilization_Packet_CPU_2.rrd


The .rrd file stores all the data, and the .info file defines the service metrics. You will face the message above if one of the files is missing. This message will also be displayed in the cmc.log:

OMD[mysite]:~$ tail -f var/log/cmc.log
2022-06-02 12:09:41 [4] [main] [rrd] [rrdcached at /omd/sites/mysite/tmp/run/rrdcached.sock] >> -1 No such file: /opt/omd/sites/mysite/var/check_mk/rrd/<HOSTNAME>/CPU_Utilization_Packet_CPU_1.rrd
2022-06-02 12:10:41 [4] [main] [rrd] [rrdcached at /omd/sites/mysite/tmp/run/rrdcached.sock] >> -1 No such file: /opt/omd/sites/mysite/var/check_mk/rrd/<HOSTNAME>/CPU_Utilization_Mgmt_CPU.rrd
2022-06-02 12:10:41 [4] [main] [rrd] [rrdcached at /omd/sites/mysite/tmp/run/rrdcached.sock] >> -1 No such file: /opt/omd/sites/mysite/var/check_mk/rrd/<HOSTNAME>/CPU_Utilization_Packet_CPU_0.rrd

Solution

Unfortunately, for some reason, one of the files is missing. In that case, it is the .rrd file. So to make the graphs work again, you need to  stop the site, find all the .info files with a missing .rrd file, and delete them manually: 

OMD[mysite]:~$ for i in $(find ~/var/check_mk/rrd -name *.info); do mysite -e ${i%info}rrd || echo $i; done
/omd/sites/mysite/var/check_mk/rrd/<HOSTNAME>/PING.info
/omd/sites/mysite/var/check_mk/rrd/<HOSTNAME>/CPU_Utilization_Mgmt_CPU.info
/omd/sites/mysite/var/check_mk/rrd/<HOSTNAME>/CPU_Utilization_Packet_CPU_1.info
/omd/sites/mysite/var/check_mk/rrd/<HOSTNAME>/CPU_Utilization_Packet_CPU_0.info


  1. Now you have a list of files to delete. Please replace echo $i with rm $i in order to delete those files.

  2. After you delete the affected files, you need to start the site to create the new files.

Checkmk does not delete any .rrd file. So it could be deleted by a custom cleaning job!