[collectd] Strange behaviour of collectd with rrdcached

[Marc]

Hello all  

I’m facing issues when using collectd alongside rrdcached: cached metrics don’t get written to disk, and I get a bunch of the following errors:

rrdcached plugin: rrdc_update (/var/lib/collectd/rrd/test_collectd/cpu-0/cpu-interrupt.rrd, [1418377171:3440], 1) failed with status -1.
Filter subsystem: Built-in target `write': Dispatching value to all write plugins failed with status -1.


The configurations used for this setup are:

### collectd client node:
FQDNLookup false
Hostname "test_collectd"
BaseDir "/var/lib/collectd"
PluginDir "/usr/lib/collectd"
Interval 10
LoadPlugin cpu
LoadPlugin load
LoadPlugin memory
LoadPlugin network
<Plugin network>
  Server “collectd-server" "25827"
</Plugin>



### collectd server node
FQDNLookup false
Hostname "collectd-server"
BaseDir "/var/lib/collectd"
PluginDir "/usr/lib/collectd"
Interval 30
LoadPlugin network
<Plugin network>
  Forward true
  Listen "0.0.0.0" "25827"
</Plugin>
LoadPlugin rrdcached
<Plugin rrdcached>
  DaemonAddress “collectd-server:42217"
  DataDir "/var/lib/collectd/rrd"
  CreateFiles true
  CollectStatistics false
</Plugin>



### /etc/default/rrdcached variables:
OPTS="-l 10.90.x.y -w 300 -z 120 -j /var/lib/rrdcached/journal”

The strange thing is: rrdcached actually creates the files, but never updates them afterwards (even after the flushing timeout). I’ve used collectd+rrdcached a few years ago and they worked fine together, but I’m presently quite confused by this issue. I’ve strace’d all the processes but found nothing suspicious.

Versions used:
- collectd 5.4.0 (tested with 5.1.0, same behaviour)
- rrdcached 1.4.7

Let me know if you need more information about my setup.

Cheers,

m.