One of the reasons I bought a SuperMicro X9DR7-LN4F for my All-in-One server was the ability to use a total of 18 drives with the on-board controllers:

• 8 disks on the LSI SAS2308 (SAS2)
• 6 drives on the Intel C602 (Port 0-5, two SATA3 and four SATA2)
• 4 drives on the SCU (SATA2).

Unfortunately this turned out not to work (running BIOS v3.0a from 10-Sep-2013, latest available at the time of writing). Thomas Krenn mentions issues with simultaneous use of the 4 SCU SATA2 ports and the SAS2308 controller. In my experience only the 2 SATA3 ports can be used when the SAS-2308 is operational rendering this this motherboard capable of supporting only 10 disks rather than 18. I would have liked to have that information before the purchase!

I ended up buying an LSI SAS 9201-16i HBA ahead of time.