How to get optimal usable capacity from new aggregate.



I have a FAS8020 and to which I added 2 DS4243 24x1TB disk shelves. I created the new aggregate with the following configurations:


45 Disks 2 spares




Raid size 15


3 raid groups of 15 disks each


total space is 28.37 TB 

Available space is 28.37 TB 


I was hoping to see way more usable space but it seems that Ontap is taking 19 TB for its self which seems way to high.


Can someone please help me determine how I can get the most space out of the aggregate.




Arsen B.