Mirrored RAID set with El Capitan / Mac

Does anyone know how to make a mirrored RAID set with a Mac that has El Capitan version 10.11.6.
In Utility Disc I do not have the option for RAID although they are mounted.

@Rodrigo_Vinas

We recently had a post on the forum about this: Link to the post

Thank you very much @Rydia