Persistence is required for the voltha core

To support high availability it is essential that, in the event of a failure, any lost component's tasks can be taken over by another.

Each voltha core is responsible for managing multiple logical switches. This requires a certain amount of state information for each device to be maintained by the core. This state information must be persisted such that, in the event of a core failure, it can be recovered by another core.

Acceptance Criteria:

• This follows that same acceptance criteria as VOL-86