Managing ceilometer data in openstack

Ceilometer can collect a large amount of data, particularly in a system with large amount of servers and high activity: in such a scenario, the numbers of meters and samples can be large which  affects ceilometer performance and gives rise to quite large databases. In our particular case we are studying energy consumption in servers and how resource utilization (mainly cpu) may relates to overall energy consumption. The energy data is collected through Kwapi and stored in ceilometer every 10 seconds (yes, this is probably too fine-grained!). We had problems that the database accumulated too quickly, filling up the root disk partition on the controller and causing significant problems for the system. In this blog post, we describe the approach we now use for managing ceilometer data which ensures that the resources consumed by ceilometer remain under control. Continue reading