RTC 5: what does the "online migration" do?
I am planning an upgrade from RTC 4.0.5 to RTC 5.0.0
I am interested in the new "online migration" procedure, because previous, offline migrations took hours to complete, resulting in an outage for RTC users.
I simulated this upgrade on a local environment, and I was surprised that, according to the RTC upgrade guide, after the online migration step, the usual offline migration step was still necessary.
Actually, in my test environment, it worked this way; first I performed an online migration, then I shut down the old server, I performed an offline migration and finally I started the new server.
So, I wonder what the online migration does, and what is its purpose.
Is it just a preparatory step that speeds the subsequent offline migration step?