This read-create StorageType records what kind of storage (such as volatile or non-volatile) backs this Policer Envelope table entry. An administrator sets it to nonVolatile when a shared envelope definition for a group of policers must survive a reboot without needing to be reconfigured. For example, a permanent envelope grouping several business-customer flows would typically be provisioned with nonVolatile storage so it is not lost on a card reset.