Although it is theoretically possible to use a full disk to house your Linux system, this is almost never done in practice. Instead, full disk block devices are split up in smaller, more manageable block devices. On most systems, these are called partitions.

If you are not interested in drawing up a partitioning scheme for your system, you can use the partitioning scheme we use throughout this book. Choose the filesystem layout that best matches the type of PowerPC system you are installing on.

Apple New World machines are fairly straightforward to configure. The first partition is always an Apple Partition Map. This partition keeps track of the layout of the disk. You cannot remove this partition. The next partition should always be a bootstrap partition. This partition contains a small (800k) HFS filesystem that holds a copy of the bootloader Yaboot and its configuration file. This partition is not the same as a /boot partition as found on other architectures. After the boot partition, the usual Linux filesystems are placed, according to the scheme below. The swap partition is a temporary storage place for when your system runs out of physical memory. The root partition will contain the filesystem that Gentoo is installed on. If you wish to dual boot, the OSX partition can go anywhere after the bootstrap partition to insure that yaboot starts first.

Apple Old World machines are a bit more complicated to configure. The first partition is always an Apple Partition Map. This partition keeps track of the layout of the disk. You cannot remove this partition. If you are using BootX, the configuration below assumes that MacOS is installed on a seperate disk. If this is not the case, there will be additional partitions for "Apple Disk Drivers" such as Apple_Driver63, Apple_Driver_ATA, Apple_FWDriver, Apple_Driver_IOKit, Apple_Patches and the MacOS install. If you are using Quik, you will need to create a boot partition to hold the kernel, unlike other Apple boot methods. After the boot partition, the usual Linux filesystems are placed, according to the scheme below. The swap partition is a temporary storage place for when your system runs out of physical memory. The root partition will contain the filesystem that Gentoo is installed on.

The Pegasos partition layout is quite simple compared to the Apple layouts. The first partition is a Boot Partition, which contains kernels to be booted, along with an Open Firmware script that presents a menu on boot. After the boot partition, the usual Linux filesystems are placed, according to the scheme below. The swap partition is a temporary storage place for when your system runs out of physical memory. The root partition will contain the filesystem that Gentoo is installed on.

The IBM PowerPC Reference Platform (PReP) requires a small PReP boot partition on the disk's first partition, followed by the swap and root partitions.

If you are interested in knowing how big a partition should be, or even how many partitions you need, read on. Otherwise continue now with Default: Using mac-fdisk (Apple) to Partition your Disk or Alternative: Using parted (IBM/Pegasos) to Partition your Disk.

The number of partitions is highly dependent on your environment. For instance, if you have lots of users, you will most likely want to have your /home separate as it increases security and makes backups easier. If you are installing Gentoo to perform as a mailserver, your /var should be separate as all received mail is stored in /var. A good choice of filesystem will then maximise your performance. Game servers should have a separate /opt as most game servers are installed there. The reason is similar for /home: security and backups. Whatever layout you chose, you will definitely want to keep /usr large: not only will it contain the majority of applications, the Portage tree alone takes more than 500Mb excluding the various sources that are stored in it.

As you can see, it very much depends on what you want to achieve. Separate partitions or volumes have the following advantages:

• You can choose the best performing filesystem for each partition or volume
• Your entire system cannot run out of free space if one defunct tool is continuously writing files to a partition or volume
• If necessary, file system checks are reduced in time, as multiple checks can be done in parallel (although this advantage is more with multiple disks than it is with multiple partitions)
• Security can be enhanced by mounting some partitions or volumes read-only, nosuid (setuid bits are ignored), noexec (executable bits are ignored) etc.

However, multiple partitions have disadvantages as well. If not configured properly, you will have a system with lots of free space on one partition and none on another. Another nuisance is that separate partitions - especially for important mountpoints like /usr or /var - often require the administrator to boot with an initramfs to mount the partition before other boot scripts start. This isn't always the case though, so YMMV.

There is also a 15-partition limit for SCSI and SATA.

Now that your partitions are created, it is time to place a filesystem on them. If you're not sure which filesystems to choose and are happy with our defaults, continue with Applying a Filesystem to a Partition. Otherwise, read on to learn about the available filesystems.

mkswap is the command that is used to initialize swap partitions:

# mkswap /dev/sda3

To activate the swap partition, use swapon:

# swapon /dev/sda3

Create and activate the swap now before creating other filesystems.

To create a filesystem on a partition or volume, there are tools available for each possible filesystem:

For instance, to make an ext3 filesystem on the root partition (/dev/sda4 in our example), you would use:

# mke2fs -j /dev/sda4

Now create the filesystems on your newly created partitions (or logical volumes).