Hot swapping the live database in cluster mode

[Buntu Dev]

New to OrientDB - trying to understand how to setup OrientDB in a cluster mode to support both the upgrades and also swapping the database in production with zero-downtime. I could find some docs related to upgrades but if I understand it correctly, there is an expected downtime during the upgrade to add/symlink the /database directory, is that correct? 

Also, I need to swap/overwrite the database with latest graph updates (say from staging database). Can I perform a rolling database update? If so, what are the best practices for doing the rolling updates to the database in a HA cluster?

Thanks!