Mac Pro APPLE RAID volume questions
The hardware RAID card is very different than the software raid so you'll want to dig into two specific tools:


System Profiler - RAID section under Hardware
RAID Utility


These two items will report the actual hardware states such as health, mirroring, degraded mode, etc... The RAID card hides the actual hardware from diskutil and Disk Utility so they are of less use than if you were doing a fusion drive or software RAID.

As to the proper setup - that really depends on which tradeoff you wish to make. Speed comes at the cost of reliability. Redundancy (or mirroring) can provide a speed up for reads but a slight slow down for writes. You'll also want to check the battery status and replace that as well as make sure you have backups of the data since RAID is not a backup but just a way to optimize for one aspect of storage over another.

Once you have a handle on the actual hardware and how the RAID card is using the drives, perhaps ask a follow on question on your options for changing things and/or a basic question asking what RAID 1 or 0 or 5 are if that's of concern.