Enabling Software RAID does have some tradeoffs:
FileVault isn’t supported.
For my server purposes, I don’t care about either of these limitations, so I’m happy that OS X Software RAID is realistic option again (the “Repair Disk” button actually works).
Here’s how I set up my new 2x1TB Mac mini Server:
SuperDuper the Mini’s boot drive (“Server HD”) onto an external drive.
Boot from the external drive.
Repartition both drives into three slices each: 50GB Boot, 50GB Boot Backup and the rest Data.
Create three new RAID 1 (Mirroring) sets encompassing those slices, respectively.
SuperDuper the external drive back onto the Boot RAID volume and boot off it.
Here’s my set-up as it appears in Disk Utility:
This set-up enables me to perform system software updates with a bootable backup safety-net in place.
I’m backing up that Data partition offsite, so I’m not backing it up locally on the Mini itself (I’m just SuperDuper’ing the Boot volume to the Boot Backup volume nightly).