Erasing, Partitioning, and Creating a RAID by Using Disk Utility
If you’re planning to erase a hard drive for a clean install or a migration, you can use Apple’s Disk Utility either before the installation process or during it. Disk Utility gives you three formatting options:
Use a simple erase.
Divide a drive into multiple partitions.
Use multiple drives together in a software RAID (redundant array of independent disks).
You can use Apple’s Disk Utility to do this formatting at the beginning of the installation process while your system is booted from a recovery drive.
Erasing or partitioning a drive
Erasing a drive in Disk Utility is similar to partitioning. Both destroy any existing data on the drive. Erasing a volume simply wipes the data off it. Partitioning a hard drive divides it into multiple volumes. Each volume appears as a separate hard drive to the user. You can use one partition as the startup disk containing OS X Server (the operating system and services) and use another, larger partition to store the user data. If something goes wrong with the user data volume, the server can keep functioning — or at least it won’t have to be re-created. This scheme also prevents the ...