High-water allocation method not working with share that has excluded disks

So I think that highwater will split when a drive hits the amount free space for 1/2 of the parity drive size - in my case 1.5T. 

 

To be precise it's supposed to split when the drive his a free space <= 1/2 your largest data drive ... NOT your parity drive.    In MOST cases that's probably the same number; but with current drive sizes it's probably not unusual to have a 4TB parity drive and no data drives that large for a while after you add the new parity drive.

Which doesn't match my results.  The copy started on my 2TB drives and when they had 1.5TB free approximately it moved to the next drive.  When it got to the 3TB drive it went beyond but only because the directory that was being copied was HUGE and it had 1.51TB free before the copy of that huge directory.  After that directory copy there was 1.18TB free.  Oh and this was a continuous copy operation from Windows box.  I selected all of the directories in Windows Explorer and pasted it into the unRAID user share and watched the ~2TB of data copy.  So for me it was based on the largest drive in the array when it figured half size and those drives with less still had the same space free.  So for 2TB drives it only used about 500GB before moving on to a new drive whereas the 3TB was >50% full.

 

That's behaving fine.  The high-water marks are computed based on the largest data drive ... so in your case that's 1/2 of 3TB = 1.5TB.  This is NOT adjusted based on the size of other drives.  So, for example, once it starts writing to the 2TB drive, it will switch again after it's down to 1.5TB (1/2 of the 3TB size).    The next "high water" mark will be 750GB (half of the 1.5GB); etc.  So, for example, if you had a 750GB drive in the array, it would remain empty until all the larger drives were down to that size.