Good Breakdown @Rich well written.
@Olga 
It only takes 1 weekend ruined for me to never do it again. Maybe I was a bit too broad. I do it during non-heavy times like Lunch and when I know MRP isn’t running or anything big.
Good breakdowns! Love it.
How does Regen work when there are multiple app servers?
Our client sysconfig file has an app server set for each user. To add a UD field, do I need to stop the other two app servers (we have 3), before I add it (in the client)? I’ll also stop the other 2 app servers first, before I stop the one I’m on, do the regen, start my app server, then start the other 2.
Is this necessary, or is Epicor smart enough to recognize a regen update from one of the other 2 app servers and get the latest version of the DB?
All 3 appservers need to be recycled (we do this all the time because of our load balancer)
Adding a UD Field definition via the UI only creates the UD Table / Field metadata. The Data Model Regen does the SQL DB update and the Data Model update.
Once you have added new UD fields via the UI, Best Practice is to stop all AppServers, do the data model regeneration (only need to do this once regardless of the number of AppServers), and then start the AppServers.
Does it matter which app server I connect to in the admin console, when I do the regen?
It does not matter.
Thanks for the @Rich discussion on all this guys (see what I did there 
) . I didn’t expect such great conversation and in depth analysis, but this was excellent. I learned a lot.
