Apple Xserve RAID: Using RAID 1.2 Admin and Disk Utility - Manual (Page 20)

20 Chapter 2 Working With RAID Arrays
Formatting and Mounting Arrays on a Host System
Creating an array creates a virtual device without a file system. You add a file system to
each RAID array on the host system using Disk Utility. The array appears in Disk Utility
as an unformatted disk.
Disk Utility is part of Mac OS X (or Mac OS X Server) and is stored in the Utilities folder
inside the Applications folder.
Important: You must use Disk Utility on the host system to format arrays and mount
them. This procedure can be done remotely with the diskutil command-line tool. Refer
to the diskutil man page for more information.
To format and mount an array on the host system:
1 Restart the host system.
In some instances, restarting the host system may not be necessary, but if you are
creating or adding arrays, you generally must restart before the arrays are visible in Disk
Utility.
2 Open Disk Utility on the host system.
3 Select the array in the list at the left side of the window.
4 Click the Erase button.