I know this question has been asked ad nauseam but it is still not clear.

 

The wiki: https://lime-technology.com/wiki/Un-Official_UnRAID_Manual#Split_level

 

Seems to refer to older terminology/examples than the current version.  "Level" instead of the more verbose "Split only the top level", etc.  It also uses diagrams which visually explain split levels but is off by one level vs. what the community and the help tooltips describe.

 

Several forum posts, such as: 

 And

Change the example by moving everything up a level from what the wiki says.

 

I am following the examples provided by the forums/community since they seem to be more up-to-date and there is more consensus, but the high water allocation isn't behaving how I would expect leading me to believe I might have my split level chosen wrong.

 

I have mine currently set up as per the Forum/Community guidelines with the expectation files get split as per the orange highlighted level below, but it does not seem to be doing that.

 

 

For example, my "Movies" share is set up to use disk 1 (8TB) and disk 2 (4TB) only, and I am currently copying my media from my old array onto this one.  Currently the 8TB disk is over 5TB used and no data has landed on the 4TB disk.  I would have expected data to start going to disk 2 once disk 1 had more than 4TB on it.

 

This leads me to believe that maybe I need to move my split level up one level from where it is, but I can't imagine that's right as the way the wiki describes level 1 would force the entire share onto one disk, making the disk inclusion/exclusion irrelevant which seems pointless to even have as an option.

 

Here are my share settings:

 

 

Here is my current capacity usage for disk 1 and 2:

 

Update: 

 

I think I had it right, but due to how rsync works (pre-populates empty folders) unraid was not able to do what I expected.

 

Trying some advice in this thread to see if it helps: