Mac Mini Server, can't set up RAID

Compared to many of you I am a novice. I'm not comfortable typing commands into Terminal, for instance.

I have a mac mini server with two hard drives and I'm trying to set it up with RAID 1.

I booted from an external drive, but I still can't reformat the disks because one of them is listed as a Logical Volume Group. What can I do?

Here is what the command came up with:

/dev/disk0

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *1.0 TB disk0

1: EFI EFI 209.7 MB disk0s1

2: Apple_HFS Macintosh HD2 999.9 GB disk0s2

/dev/disk1

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *1.0 TB disk1

1: EFI EFI 209.7 MB disk1s1

2: Apple_CoreStorage 999.3 GB disk1s2

3: Apple_Boot Recovery HD 650.0 MB disk1s3

/dev/disk2

#: TYPE NAME SIZE IDENTIFIER

0: Apple_HFS Macintosh HD *999.0 GB disk2

Logical Volume on disk1s2

D750B132-296C-472D-97B2-F7B2A9924C5D

Unencrypted

/dev/disk3

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *251.0 GB disk3

1: EFI EFI 209.7 MB disk3s1

2: Apple_HFS Macintosh HD 250.1 GB disk3s2

3: Apple_Boot Recovery HD 650.0 MB disk3s3