FOT vs live failover

Hello,

Mike from Zerto here.

For explanations of both processes, see the following links:

http://s3.amazonaws.com/zertodownload_docs/Latest/Zerto%20Virtual%20Replication%20Zerto%20Virtual%20Manager%20(ZVM)%20-%20vSphere%20Online%20Help/content/adminvc/the_test_failover_process.htm

http://s3.amazonaws.com/zertodownload_docs/Latest/Zerto%20Virtual%20Replication%20Zerto%20Virtual%20Manager%20(ZVM)%20-%20vSphere%20Online%20Help/content/adminvc/the_failover_live_process.htm

To answer your question more directly, if you select Reverse Protection when you perform a Live Failover, there will be a reverse delta sync after you commit the Failover. There is no reverse delta sync on a Test Failover, because there is no reversing the protection for a Test Failover. A Test Failover is meant to be an isolated test, so production is never affected, and there would be no replication back to the production site.