Extents can be rebalanced by strictly enforcing the allocation policy. Rebalancing is generally required when volumes are added or removed from the policy or when the chunk size is modified. When volumes are removed from the volume set, any extents on the volumes being removed are automatically relocated to other volumes within the policy.
The following example redefines a policy that has four volumes by adding two new volumes, removing an existing volume, and enforcing the policy for rebalancing.