The version of Disk Utility that comes with the new Mac Mini's is unique and it want's to merge the drives into one Fusion Drive. The other bad news to this is, that older versions of Disk Utility will not work with the OS X build that is on that Mac Mini.
Have a look at > Mac mini (Late 2012) and iMac (Late 2012): About Fusion Drive
There are lots of advantages to Fusion Drives.
There are advantages to keeping the HDD and the SSD as separate volumes.
Here's the information you need to keep your current Fusion Drive, or to break it up:
With a 256gb SSD, you have plenty of room for all the OS's files plus applications and your most commonly-accessed data and therefore you might be better off keeping each physical drive as a separate volume. At least, that's what I'd do myself if my SSD were that large. Mine is only 128gb, though, so I get a lot of value from the automatic swapping between the two physical drives across the single logical volume of the Fusion Drive.
Currently Being ModeratedSep 20, 2013 11:56 AM (in response to John Hammer1)
I encountered an issue today where a single Seagate 3TB SATA drive on a 2009 27-inch iMac had somehow morphed itself into a logical volume group and wouldn't allow deletion of the partition/repartitioning in Disk Utility. Googling and searching here on the discussions group helped me find the MacWorld articles posted by John Hammer1 of NYC. The article he references:
solved the issue but what was puzzling was how a SINGLE drive w/1 partition (created 6/13 with Disk Utility 10.8.4) somehow morphed into a logical volume. Ideas or other related experiences?
Currently Being ModeratedFeb 25, 2014 10:46 PM (in response to ericb11)
So, now if 10.9.2 fixes the audio issue, can someone walk me through how to merge the splitted fusion drive and and also how to get the homefolder back on the merged drive? Now it is placed on the internal HDD part of the splitted fusion drive. Thankful for help or hints./Niklas