I have a DL380 G9 with 12x8TB 3.5" disks:
| 1 | 4 | 7 | 10 |
| 2 | 5 | 8 | 11 |
| 3 | 6 | 9 | 12 |
In the Smart Array Controller GUI, if I select all 12 disks and assign them to a RAID 50 array, how will the controller divide the disks for the RAID 5 arrays?
Will drives 1-6 and 7-12 inclusive be in two separate RAID 5 arrays, striped for RAID 0? Or will drives 1-3, 4-6, 7-9, and 10-12 be in four separate RAID 5 arrays striped for RAID 0?
If it's the former by default, is it possible to manually configure the array to the latter?
The number of RAID5 sets for RAID0 should be able to configure in raid utility. In your case you can select 2 (6 disks in RAID5), 3 (4 disks in RAID5) or 4(3 disks in RAID5). From perfromance and capacity perspective - 2 RAID5 sets is most preferable in your case.
P.S. RAID50 tolerates only one disk failure (second disk failure from same RAID5 set will bring whole system down)