The following flavor extra specs can be used to rate limit storage IO to the Ceph cluster.
disk_read_bytes_sec
disk_read_iops_sec
disk_write_bytes_sec
disk_write_iops_sec
disk_total_bytes_sec
disk_total_iops_sec
When provisioning virtual machines these flavor extra specs are copied to the instance and cannot be changed with the Nova API. The only way to update the instance's extra_specs is by directly updating the database table and restarting the virtual machine.