container's will be deleted by the container-replicator after their reclaim age has passed. The reclaim age is configurable:

http://docs.openstack.org/developer/s...

go down the "container-replicator" section

It is not safe to delete to delete the containers any sooner that the consistency engine cycle time because it can lead to ghost entries in the accounts.

You can also turn down the concurrency and interval on the container updater.

But the container's won't actually updating if they're fully reported, so the only overhead should be the quick check on the container_stat table for the reported timestamps and the io of container-updaters file system walk - which you should be able to tune to the load and capabilities of your system.