If you’ve purchased a Mac mini Server you’ll realize that the default configuration is two 500GB hard drives. If you do not need more than 500GB of storage you can use that second drive to add redundancy. By mirroring the two drives together you have the ability withstand a drive failure and not lose any data. However, it does not replace a standard backup policy! You mirror the drives by setting up a software RAID. RAID stands for Redundant Array of Independent Disks, and there are many levels of RAID configuration. The one we are focusing on is RAID 1 or “mirroring”. Heres how to easily make the change over to RAID 1:
First things first. We have no DVD drive in a Mac mini Server. You can easily remedy this by using a USB DVD drive (hold down “C” while turning your mini on). The other option is to use another computer’s DVD drive. To do that, follow the steps in the Apple Knowledge Base Article link below. We want to boot off the OS X Server disk that was included with the mini.
Once we’ve booted the OS X Server disk and selected your language, you’ll want to use the Disk Utility program under the Utilities menu. Use the RAID tab and drag both drives over to create a new mirrored set. Warning, you will lose any data on these drives.* Create a standard Mac OS Extended Journaled volume. Apply your changes and exit the Disk Utility. Continue installing OS X to the destination drive (RAID Volume) you just created. See the following Apple Knowledge Base Article for details more details.
*Update: If you are brave and your data is backed up (we always recommend you have a good backup policy) – you can try to use the Terminal after booting off the OS X disk instead of the Disk Utility to build the array without destroying data:
diskutil appleRAID enable mirror [PRIMARY DISK]
You can then reboot and add the second drive to the RAID and kick off the rebuild.
diskutil AppleRAID add member [SECOND DISK] [RAID]
You can open Disk Utility and click into the RAID volume and use the rebuild button under the RAID tab to kick off the rebuild process. You can check up on the status of the rebuild by re-running the checkRAID command: