Ok, so here is the basic picture of how my raid card sees my disks:
All 6 disks should be in the same array, but it seems the controller now thinks there are two arrays.
Taking a closer look at the first one, it shows that it should be the full 1.5TB
Taking a closer look at the second one, it shows that it should also be the full 1.5TB. Hrm.
All of the individual disks are showing "OK", none are reporting failed.