[ceilometer] Missing some notifications

Hi, I am not sure if this problem is related to ceilometer or rabbitmq but it looks like our ceilometer notification agent is missing some notifications. Creating, eg. 10 cinder volumes in a row results in some of those volumes are not stored in gnocchi. "openstack metric resource show <ID>" results in a 404 error. Attaching the volume and detaching it again sometimes helps to "create" it in gnocchi. We do use gnocchi for billing. So missing volumes is very bad. Any recommendation on how to debug this problem? Thank you very much, flo