If you're using hard drives for backups, you may wish to partition the disks. (To determine how large each partition should be, review Does Size Matter?, page 118.) To partition a hard disk:
After connecting the drive, launch Disk Utility.
From the list on the left, select the hard disk you want to partition, and click the Partition tab on the right.
Under Volume Scheme, choose the number of partitions you want. For each partition, give it a name, and choose a format. Mac OS Extended (Journaled) is the default and recommended choice.
Warning! If you want to be able to boot into Mac OS 9 from this volume (and if your machine supports that option), be sure the Install Mac OS 9 Disk Drivers checkbox is selected. (This setting applies to the whole disk, not to a particular volume.) You can't change this later without erasing the disk again, so if in doubt, leave the box checked.
Resize the partitions manually by dragging the dividers, or enter a size for each partition.
When you're happy with your settings, click Partition. You can then quit Disk Utility.
Partitioning without Reformatting?
Four new utilities promise the capability of partitioning your hard disk without having to reformat it first, preserving all your data. I haven't tested them thoroughly, so I strongly recommend that you not attempt to repartition a drive without backing it up first.
Drive Genius: This $99 application from Prosoft Engineering includes disk testing, repair, and optimization features. You can also use it to add, delete, or resize partitions without reformatting a drivethough the current version cannot merge two partitions while keeping the data from both intact (www.prosofteng.com).
VolumeWorks: The $60 VolumeWorks from SubRosaSoft is basically the partitioning portion of Drive Genius packaged as a stand-alone product (www.subrosasoft.com).
DiskStudio: Micromat's DiskStudio is a $50 application that provides only partitioning tools, not testing or repair. Like Drive Genius, it can add partitions without erasing data or delete partitions while leaving the rest of the disk intact. However, it currently offers no mechanism for resizing partitions (www.micromat.com).
iPartition: From Coriolis Systems, the $45 iPartition, like DiskStudio, is strictly a partitioning tool. Unlike DiskStudio, it has the capability of resizing partitions without erasing your data. The only significant limitation is that it does not include its own bootable CDto use it on your startup disk, you must boot from another volume or create your own bootable CD that includes iPartition (www.coriolis-systems.com).
Your hard disk is now partitioned into multiple volumes, each of which will show up in the Finder as an independent disk.