How should one connect a small storage array, four 3TB SATA drives for now, to two motherboards or controllers as a failover system? This means avoiding adding another single point of failure such as a single SAN device. A perfect world would have a [non-RAID] controller on an expansion card (PCIe, PCIX) made for exactly this task, or have the capability built into common motherboards.
I'm avoiding hardware RAID cards as this is just a backup solution, not a high performance server, and will be implementing ZFS (RAID-Z2, similar to RAID-6).