task.event.lightweight behaviour in 8.0

I want know the behaviour of ‘task.event.lightweight’ parameter in 8.0.
There is no documentation on the same. Since CAF events do exist in 8.0, i am sure they are being handled in some way.

We have an active-passive config for MWS. where one is used for disaster recovery.
Both the servers point to the same DB and same Broker.
During disaster recovery , we bring down primary , bring up secondary and we route requests to the new Server using load balancer routing. But last time, some of the CAF events fired during this activity and we can see that in sercondary server logs when it was up and the process got stuck as the events were supposed to queue task and process steps. We are analysing that behaviour.

I can find the Following in ‘8-2-SP1_Task_Engine_Users_Guide.pdf’ on page 172.

'Storing Task Events Persistently
You can set the following option to enable in-memory event handling:
This default value is true. When true, the Task Engine does not use the JMS queue for
processing task events and all events are processed locally on the same JVM instance
where they were originated. This producesless database load and thus speeds up
processing. The disadvantage of using this setting is that there is bigger chance for events
to left unprocessed if system shuts down unexpectedly or fails.
To overcome this, you can use a related option to specify if task events are to be
maintained in system memory, orpersistently stored to disk. The default setting (false) is
to use system memory. The option is:
When persisting task events to disk (true), the processingof each task change event to
disk imposes a performance penalty, but adds quality of service. For example, if a system
shuts down unexpectedly or fails while there are unprocessed eventsin the queue, the
system can recover them from the disk store and continue processing when restarted.
When task events are stored in memory (false), these events will be lost upon shutdown
or failure. This can result in queued tasks not getting assigned (that is, the tasks were
queued but not yet assigned when the shutdown or failure occurred).
The -Dtask.event.lightweight.persistentoption is active only when -
Dtask.event.lightweightis set to true."