Configurando Raid iMac

A partir de El Capitán, la aplicación Utilidad de disco ya no proporciona la funcionalidad RAID, pero permanece en el programa de línea de comandos diskutil . Para obtener instrucciones breves, escriba diskutil appleRAID o diskutil appleRAID create en el terminal. Para obtener información más detallada, escriba man diskutil .

Lista de comandos RAID disponibles:

askewchan ~> diskutil appleRAID
Usage:  diskutil [quiet] appleRAID|AR <raidverb> <options>,
        where <raidverb> is as follows:

     list            (Display the current status of RAID sets)
     create          (Create a RAID set on multiple disks)
     delete          (Delete an existing RAID set)
     repairMirror    (Repair a damaged RAID mirror set)
     add             (Add a spare or member disk to an existing RAID)
     remove          (Remove a spare or member disk from an existing RAID)
     enable          (Convert a volume into a single disk RAID set)
     update          (Update the settings of an existing RAID)

diskutil appleRAID <raidverb> with no options will provide help on that verb

El comando create :

askewchan ~> diskutil appleRAID create
Usage:  diskutil appleRAID create mirror|stripe|concat setName
        filesystemType MemberDeviceNames|NestedRAIDSetUUIDs ...
Create a RAID set.  All existing data on the drives will be lost.
Ownership of the affected disks is required.
Example: diskutil AppleRAID create mirror MirrorName JHFS+ disk1 disk2

Algunas partes relevantes de la página man completa:

askewchan ~> man diskutil

DISKUTIL(8)               BSD System Manager's Manual              DISKUTIL(8)

NAME
    diskutil -- modify, verify and repair local disks

SYNOPSIS
    diskutil [quiet] verb [options]

DESCRIPTION
    diskutil manipulates the structure of local disks.  It provides information
    about, and allows the administration of, the partitioning schemes, layouts, and
    formats of disks. This includes hard disks, solid state disks, optical discs,
    CoreStorage volumes, and AppleRAID sets.  It generally manipulates whole vol-
    umes instead of individual files and directories.

En RAID:

appleRAID | ar raidVerb [...]
    AppleRAID verbs can be used to create, manipulate and destroy
    AppleRAID volumes (Software RAID).  AppleRAID supports three basic
    types of RAID sets:

          o   "stripe" - Striped Volume (RAID 0)
          o   "mirror" - Mirrored Volume (RAID 1)
          o   "concat" - Concatenated Volume (Spanning)

    Of these three basic types, only the "mirror" type increases fault-
    tolerance.  Mirrors may have more than two disks to further increase
    their fault-tolerance.  Striped and concatentated volumes are, in
    fact, more vulnerable to faults than single disk volumes.

    AppleRAID is not a replacement for backing up your data.  Backups
    should be always be performed on a regular basis and before modify-
    ing any RAID set using these commands.

Al crear un nuevo RAID:

    create mirror | stripe | concat setName format devices ...
               Create a new RAID set consisting of multiple disks and/or
               RAID sets.  setName is used for both the name of the cre-
               ated RAID volume and the RAID set itself (as displayed in
               list). e.g. 'diskutil createRAID stripe MyArray JHFS+
               disk1 disk2 disk3 disk4'.  Ownership of the affected
               disks is required.  diskutil createRAID is a deprecated
               synonym for diskutil appleRAID create.

Fácil, el programa Disk Utility en OS X permite la creación de software RAID.

• Abra la Utilidad de Disco desde Spotlight o / Aplicaciones / Utilidades
• Escriba "Crear RAID" en el término de búsqueda del menú de ayuda
• Vaya al artículo y siga los pasos para Crear un conjunto RAID duplicado

Esto implica borrar todas las unidades, así que querrás estar seguro de que todo está respaldado en otra parte antes de comenzar. En 10.11 El Capitan, esta función de la herramienta gráfica Utilidad de disco se eliminó, por lo que necesitaría llamar al comando subyacente diskutil que aún tiene los comandos RAID.