Comment 0 for bug 2003839

This is a spin off from bug 1971093, not a regression as we had no collectd at all, but waiting on Upstream to respond.

We will link the upstream case and chime in there, hoping to get some insight.

Issue: https://github.com/collectd/collectd/issues/3963

Repro:
$ apt install collectd

Change default config to:

<Plugin rrdtool>
 DataDir "/var/lib/collectd/rrd"
 CacheTimeout 10
 CacheFlush 900
 RandomTimeout 5

$ rm -rf /var/lib/collectd/rrd/*

Check the service output:
$ journalctl -f -u collectd

$ systemctl restart collectd

Notes:
- I can only see that
  a) while stopping the service
  b) after deleting DataDir

Others (https://bugs.launchpad.net/ubuntu/+source/collectd/+bug/1971093/comments/33) have reported to see it more than once. I'm unsure if failing with a warning on deleted data is too much of a real problem. We need to find if this can also occur in other more critical scenarios.