Partitioning Disks
For the most part, you’ll want to assign a single volume to each of your hard drives. It’s quick, easy, and is usually the most efficient use of space. However, there are times when you might want to have more than one volume on a drive. For example, while working with the first few releases of a new version of Mac OS X, you might want to have a test partition for the new version while keeping a stable, known version available. Or you might want to keep an old copy of Mac OS 9 available on a separate partition from your Mac OS X installation for running Classic.
Tip
The best and only time to partition your disk is when you’re installing the operating system. Once the system is installed, you can’t go back later and partition the drive or adjust the partition sizes. So, if you want to partition your drive, you must first back up all your critical data to another drive, and then do a clean install of Mac OS X using the Disk Utility on the Install DVD. For details on partitioning and installing Mac OS X, see Chapter 2.
To create multiple volumes on a disk, select the disk that you want to divide and click the Partition tab. This brings up an interface that lets you configure how much space to give each volume on a disk, as shown in Figure 9-9. From the volume scheme pop-up menu choose the number of partitions you want and size them however you want by either using the graphical tool or typing sizes for each partition. Then click the Partition button to commit the changes. ...