Gnoocchi do not delete old metrics

Issue

• After configured a ceilometer expiration time to 7 days, Gnocchi never delete old metrics.
• However I have 259175 ressource store in /var/lib/gnocchi. That's generate a lot of iops.

• How to clean them ?

  [root@jncloud-controller-1 gnocchi]$ for i in /var/lib/gnocchi/*; do echo $i;done|wc -l
  259175
  

• Example with an old metrics : More than 4 Mounths ...

  [root@jncloud-controller-1 gnocchi]$ ll  -d 34e40478-b031-4a68-9b3b-49ae25a54b73
  drwxr-x---. 8 gnocchi gnocchi 4096 Sep 13 17:48 34e40478-b031-4a68-9b3b-49ae25a54b73