It is based on the right sized capacity.  So if this was The Price is Right, the 105 would win.  I think the actual answer is 107.

Tim

From: toasters-bounces@teaparty.net [mailto:toasters-bounces@teaparty.net] On Behalf Of Jeffrey Mohler
Sent: Monday, February 08, 2016 8:24 PM
To: Toasters
Subject: Max Aggr Size is based on..

Marketing disk size (4T)

Or..

Raw block size (3.815T)

Which makes a 400T aggr either 100 disks, or 105.

Beer bet to settle here.   :)