ME4 ADAPT Usable Space Formula

Hello all,

 

I'm trying to find some more information about the ADAPT RAID level with the ME4 Series. From what I can find ADAPT will set aside the capacity of your  2 largest drive for spare, however, what I'm having difficulty finding is the overall usable capacity of an ADAPT disk group.

 

For instance, if i have a Disk Group of  22 - 10TB Drive(Hotspare 2ea), 

When i configuration Raid 6, Formula is:

10TB*20=200TB-20TB(10*2 Parity) = 180 - 10% = (About) Usable 162TB

 

So, Then what is the formula for ADAPT Raid?