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<?xml version='1.0' encoding='UTF-8'?>
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<!DOCTYPE sections SYSTEM "/dtd/book.dtd">
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<!-- The content of this document is licensed under the CC-BY-SA license -->
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<!-- See http://creativecommons.org/licenses/by-sa/1.0 -->
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<!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/handbook/hb-install-ppc-disk.xml,v 1.11 2004/07/26 09:04:42 dertobi123 Exp $ -->
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<sections>
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<section>
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<title>Introduction to Block Devices</title>
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<subsection>
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<title>Block Devices</title>
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<body>
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<p>
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We'll take a good look at disk-oriented aspects of Gentoo Linux
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and Linux in general, including Linux filesystems, partitions and block devices.
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Then, once you're familiar with the ins and outs of disks and filesystems,
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you'll be guided through the process of setting up partitions and filesystems
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for your Gentoo Linux installation.
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</p>
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<p>
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To begin, we'll introduce <e>block devices</e>. The most famous block device is
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probably the one that represents the first IDE drive in a Linux system, namely
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<path>/dev/hda</path>. If your system uses SCSI drives, then your first hard
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drive would be <path>/dev/sda</path>.
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</p>
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<p>
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The block devices above represent an abstract interface to the disk. User
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programs can use these block devices to interact with your disk without worrying
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about whether your drives are IDE, SCSI or something else. The program can
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simply address the storage on the disk as a bunch of contiguous,
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randomly-accessible 512-byte blocks.
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</p>
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</body>
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</subsection>
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<subsection>
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<title>Partitions and Slices</title>
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<body>
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<p>
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Although it is theoretically possible to use a full disk to house your Linux
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system, this is almost never done in practice. Instead, full disk block devices
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are split up in smaller, more manageable block devices. On most systems,
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these are called <e>partitions</e>. Other architectures use a similar technique,
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called <e>slices</e>.
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</p>
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</body>
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</subsection>
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</section>
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<section>
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<title>Designing a Partitioning Scheme</title>
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<subsection>
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<title>Default Partitioning Scheme</title>
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<body>
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<p>
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If you are not interested in drawing up a partitioning scheme for your system,
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you can use the partitioning scheme we use throughout this book:
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</p>
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<table>
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<tr>
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<th>Partition NewWorld</th>
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<th>Partition OldWorld</th>
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<th>Partition Pegasos</th>
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<th>Filesystem</th>
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<th>Size</th>
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<th>Description</th>
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</tr>
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<tr>
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<ti><path>/dev/hda1</path></ti>
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<ti>(Not needed)</ti>
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<ti>(Not applicable)</ti>
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<ti>(bootstrap)</ti>
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<ti>800k</ti>
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<ti>Apple_Bootstrap</ti>
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</tr>
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<tr>
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<ti><path>/dev/hda2</path></ti>
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<ti><path>/dev/hda1</path></ti>
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<ti><path>/dev/hda1</path></ti>
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<ti>(swap)</ti>
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<ti>512M</ti>
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<ti>Swap partition</ti>
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</tr>
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<tr>
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<ti><path>/dev/hda3</path></ti>
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<ti><path>/dev/hda2</path></ti>
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<ti><path>/dev/hda2</path></ti>
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<ti>ext3</ti>
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<ti>Rest of the disk</ti>
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<ti>Root partition</ti>
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</tr>
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</table>
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<p>
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If you are interested in knowing how big a partition should be, or even how
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many partitions you need, read on. Otherwise continue now with
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<uri link="#fdisk">Default: Using mac-fdisk (Apple/IBM) to Partition your
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Disk</uri> or <uri link="#parted">Alternative: Using parted (especially Pegasos) to
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Partition your Disk</uri>.
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</p>
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</body>
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</subsection>
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<subsection>
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<title>How Many and How Big?</title>
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<body>
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<p>
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The number of partitions is highly dependent on your environment. For instance,
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if you have lots of users, you will most likely want to have your
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<path>/home</path> separate as it increases security and makes backups easier.
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If you are installing Gentoo to perform as a mailserver, your
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<path>/var</path> should be separate as all mails are stored inside
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<path>/var</path>. A good choice of filesystem will then maximise your
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performance. Gameservers will have a separate <path>/opt</path> as most gaming
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servers are installed there. The reason is similar for <path>/home</path>:
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security and backups.
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</p>
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<p>
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As you can see, it very much depends on what you want to achieve. Separate
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partitions or volumes have the following advantages:
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</p>
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<ul>
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<li>
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You can choose the best performing filesystem for each partition or volume
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</li>
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<li>
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Your entire system cannot run out of free space if one defunct tool is
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continuously writing files to a partition or volume
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</li>
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<li>
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If necessary, file system checks are reduced in time, as multiple checks can
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be done in parallel (although this advantage is more with multiple disks than
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it is with multiple partitions)
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</li>
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<li>
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Security can be enhanced by mounting some partitions or volumes read-only,
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nosuid (setuid bits are ignored), noexec (executable bits are ignored) etc.
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</li>
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</ul>
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<p>
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However, multiple partitions have one big disadvantage: if not configured
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properly, you might result in having a system with lots
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of free space on one partition and none on another.
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</p>
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</body>
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</subsection>
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</section>
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<section id="fdisk">
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<title>Default: Using mac-fdisk (Apple/IBM) Partition your Disk</title>
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<body>
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<p>
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At this point, create your partitions using <c>mac-fdisk</c>:
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</p>
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<pre caption="Starting mac-fdisk">
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# <i>mac-fdisk /dev/hda</i>
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</pre>
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<p>
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First delete the partitions you have cleared previously to make room for your
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Linux partitions. Use <c>d</c> in <c>mac-fdisk</c> to delete those partition(s).
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It will ask for the partition number to delete.
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</p>
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<p>
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Second, create an <e>Apple_Bootstrap</e> partition by using <c>b</c>. It will
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ask for what block you want to start. Enter the number of your first free
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partition, followed by a <c>p</c>. For instance this is <c>1p</c>.
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</p>
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<note>
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This partition is <e>not</e> a "boot" partition. It is not used by Linux at all;
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you don't have to place any filesystem on it and you should never mount it. PPC
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users don't need a an extra partition for <path>/boot</path>.
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</note>
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<p>
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Now create a swap partition by pressing <c>c</c>. Again <c>mac-fdisk</c> will
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ask for what block you want to start this partition from. As we used <c>1</c>
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before to create the Apple_Bootstrap partition, you now have to enter
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<c>2p</c>. When you're asked for the size, enter <c>512M</c> (or whatever size
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you want -- 512MB is recommended though). When asked for a name, enter <c>swap</c>
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(mandatory).
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</p>
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<p>
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To create the root partition, enter <c>c</c>, followed by <c>3p</c> to select
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from what block the root partition should start. When asked for the size, enter
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<c>3p</c> again. <c>mac-fdisk</c> will interpret this as "Use all available
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space". When asked for the name, enter <c>root</c> (mandatory).
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</p>
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<p>
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To finish up, write the partition to the disk using <c>w</c> and <c>q</c> to
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quit <c>mac-fdisk</c>.
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</p>
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<p>
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Now that your partitions are created, you can now continue with <uri
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link="#filesystems">Creating Filesystems</uri>.
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</p>
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</body>
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</section>
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<section id="parted">
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<title>Using parted (especially Pegasos) to Partition your Disk</title>
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<body>
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<p>
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<c>parted</c>, the Partition Editor, can now handle HFS+ partitions used by
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Mac OS and Mac OS X. With this tool you can shrink your Mac-partitions and
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create space for your Linux partitions. Nevertheless, the example below
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describes partitioning for Pegasos machines only.
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</p>
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<p>
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To begin let's fire up <c>parted</c>:
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</p>
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<pre caption="Starting parted">
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# <i>parted /dev/hda</i>
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</pre>
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<p>
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If the drive is unpartitioned, run <c>mklabel amiga</c> to create a new
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disklabel for the drive.
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</p>
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<p>
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You can type <c>print</c> at any time in parted to display the current partition
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table. Your changes aren't saved until you quit the application; if at any time
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you change your mind or made a mistake you can press <c>Ctrl-c</c> to abort
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parted.
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</p>
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<p>
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If you intend to also install MorphOS on your Pegasos create an affs1 filesystem
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named "BI0" (BI zero) at the start of the drive. 50MB should be more than enough
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to store the MorphOS kernel. If you have a Pegasos I or intend to use reiserfs,
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xfs or jfs you will also have to store your Linux kernel on this partition (the
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Pegasos II can boot from ext2/ext3 drives). To create the partition run
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<c>mkpart primary affs1 START END</c> where <c>START</c> and <c>END</c> should
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be replaced with the megabyte range (f.i. <c>5 55</c> creates a 50 MB partition
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starting at 5MB and ending at 55MB.
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</p>
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<p>
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You need to create two partitions for Linux, one root filesystem for all your
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program files etc, and one swap partition. To create the root filesystem you
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must first decide which filesystem to use. Possible options are ext2, ext3,
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reiserfs, jfs and xfs. Unless you know what you are doing, use ext3. Run
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<c>mkpart primary ext3 START END</c> to create an ext3 partition. Again, replace
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<c>START</c> and <c>END</c> with the megabyte start and stop marks for the
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partition.
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</p>
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<p>
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It is generally recommended that you create a swap partition the same size as
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the amount of RAM in your computer times two. You will probably get away with a
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smaller swap partition unless you intend to run a lot of applications at the
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same time (although at least 512MB is recommended). To create the swap
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partition, run <c>mkpart primary linux-swap START END</c>.
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</p>
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<p>
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Write down the partition minor numbers as they are required during the
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installation process. To dislay the minor numbers run <c>print</c>. Your drives
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are accessed as <path>/dev/hdaX</path> where X is replaced with the minor number
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of the partition.
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</p>
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<p>
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When you are done in parted simply run <c>quit</c>.
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</p>
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</body>
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</section>
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<section id="filesystems">
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<title>Creating Filesystems</title>
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<subsection>
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<title>Introduction</title>
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<body>
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<p>
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Now that your partitions are created, it is time to place a filesystem on them.
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If you don't care about what filesystem to choose and are happy with what we use
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as default in this handbook, continue with <uri
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link="#filesystems-apply">Applying a Filesystem to a Partition</uri>.
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Otherwise read on to learn about the available filesystems...
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</p>
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</body>
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</subsection>
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<subsection>
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<title>Filesystems?</title>
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<body>
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<p>
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Several filesystems are available. ext2 and ext3 are found stable on the
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PPC architecture, reiserfs and xfs are in testing stage, though we did not
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encountered any serious errors with the 2.6 Linux kernel. jfs is
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unsupported.
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</p>
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<p>
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<b>ext2</b> is the tried and true Linux filesystem but doesn't have metadata
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journaling, which means that routine ext2 filesystem checks at startup time can
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be quite time-consuming. There is now quite a selection of newer-generation
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journaled filesystems that can be checked for consistency very quickly and are
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thus generally preferred over their non-journaled counterparts. Journaled
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filesystems prevent long delays when you boot your system and your filesystem
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happens to be in an inconsistent state.
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</p>
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| 328 |
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<p>
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<b>ext3</b> is the journaled version of the ext2 filesystem, providing metadata
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journaling for fast recovery in addition to other enhanced journaling modes like
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full data and ordered data journaling. ext3 is a very good and reliable
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filesystem. It has an additional hashed b-tree indexing option that enables
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high performance in almost all situations. In short, ext3 is an excellent
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filesystem.
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| 336 |
</p>
|
| 337 |
|
| 338 |
<p>
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| 339 |
<b>ReiserFS</b> is a B*-tree based filesystem that has very good overall
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performance and greatly outperforms both ext2 and ext3 when dealing with small
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files (files less than 4k), often by a factor of 10x-15x. ReiserFS also scales
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extremely well and has metadata journaling. As of kernel 2.4.18+, ReiserFS is
|
| 343 |
solid and usable as both general-purpose filesystem and for extreme cases such
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| 344 |
as the creation of large filesystems, the use of many small files, very large
|
| 345 |
files and directories containing tens of thousands of files.
|
| 346 |
</p>
|
| 347 |
|
| 348 |
<p>
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| 349 |
<b>XFS</b> is a filesystem with metadata journaling which comes with a robust
|
| 350 |
feature-set and is optimized for scalability. We only recommend using this
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| 351 |
filesystem on Linux systems with high-end SCSI and/or fibre channel storage and
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| 352 |
an uninterruptible power supply. Because XFS aggressively caches in-transit data
|
| 353 |
in RAM, improperly designed programs (those that don't take proper precautions
|
| 354 |
when writing files to disk and there are quite a few of them) can lose a good
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| 355 |
deal of data if the system goes down unexpectedly.
|
| 356 |
</p>
|
| 357 |
|
| 358 |
<p>
|
| 359 |
<b>JFS</b> is IBM's high-performance journaling filesystem. It has recently
|
| 360 |
become production-ready and there hasn't been a sufficient track record to
|
| 361 |
comment positively nor negatively on its general stability at this point.
|
| 362 |
</p>
|
| 363 |
|
| 364 |
</body>
|
| 365 |
</subsection>
|
| 366 |
<subsection id="filesystems-apply">
|
| 367 |
<title>Applying a Filesystem to a Partition</title>
|
| 368 |
<body>
|
| 369 |
|
| 370 |
<p>
|
| 371 |
To create a filesystem on a partition or volume, there are tools available for
|
| 372 |
each possible filesystem:
|
| 373 |
</p>
|
| 374 |
|
| 375 |
<table>
|
| 376 |
<tr>
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| 377 |
<th>Filesystem</th>
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| 378 |
<th>Creation Command</th>
|
| 379 |
</tr>
|
| 380 |
<tr>
|
| 381 |
<ti>ext2</ti>
|
| 382 |
<ti><c>mke2fs</c></ti>
|
| 383 |
</tr>
|
| 384 |
<tr>
|
| 385 |
<ti>ext3</ti>
|
| 386 |
<ti><c>mke2fs -j</c></ti>
|
| 387 |
</tr>
|
| 388 |
<tr>
|
| 389 |
<ti>reiserfs</ti>
|
| 390 |
<ti><c>mkreiserfs</c></ti>
|
| 391 |
</tr>
|
| 392 |
<tr>
|
| 393 |
<ti>xfs</ti>
|
| 394 |
<ti><c>mkfs.xfs</c></ti>
|
| 395 |
</tr>
|
| 396 |
<tr>
|
| 397 |
<ti>jfs</ti>
|
| 398 |
<ti><c>mkfs.jfs</c></ti>
|
| 399 |
</tr>
|
| 400 |
</table>
|
| 401 |
|
| 402 |
<p>
|
| 403 |
For instance, to have the root partition (<path>/dev/hda3</path> in our example)
|
| 404 |
in ext3 (as in our example), you would use:
|
| 405 |
</p>
|
| 406 |
|
| 407 |
<pre caption="Applying a filesystem on a partition">
|
| 408 |
# <i>mke2fs -j /dev/hda3</i>
|
| 409 |
</pre>
|
| 410 |
|
| 411 |
<p>
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| 412 |
Now create the filesystems on your newly created partitions (or logical
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| 413 |
volumes).
|
| 414 |
</p>
|
| 415 |
|
| 416 |
<note>
|
| 417 |
Be sure that the partition which will host your kernel (the
|
| 418 |
<path>/boot</path>-path) must be ext2 or ext3. The bootloader can only handle
|
| 419 |
this filesystem.
|
| 420 |
</note>
|
| 421 |
|
| 422 |
</body>
|
| 423 |
</subsection>
|
| 424 |
<subsection>
|
| 425 |
<title>Activating the Swap Partition</title>
|
| 426 |
<body>
|
| 427 |
|
| 428 |
<p>
|
| 429 |
<c>mkswap</c> is the command that is used to initialize swap partitions:
|
| 430 |
</p>
|
| 431 |
|
| 432 |
<pre caption="Creating a Swap signature">
|
| 433 |
# <i>mkswap /dev/hda2</i>
|
| 434 |
</pre>
|
| 435 |
|
| 436 |
<p>
|
| 437 |
To activate the swap partition, use <c>swapon</c>:
|
| 438 |
</p>
|
| 439 |
|
| 440 |
<pre caption="Activating the swap partition">
|
| 441 |
# <i>swapon /dev/hda2</i>
|
| 442 |
</pre>
|
| 443 |
|
| 444 |
<p>
|
| 445 |
Create and activate the swap now.
|
| 446 |
</p>
|
| 447 |
|
| 448 |
</body>
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</subsection>
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</section>
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<section>
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<title>Mounting</title>
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<body>
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| 454 |
|
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<p>
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Now that your partitions are initialized and are housing a filesystem, it is
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time to mount those partitions. Use the <c>mount</c> command. Don't forget to
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create the necessary mount directories for every partition you created. As an
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example we create a mount-point and mount the root and boot partition:
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</p>
|
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<pre caption="Mounting partitions">
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# <i>mkdir /mnt/gentoo</i>
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# <i>mount /dev/hda3 /mnt/gentoo</i>
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</pre>
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<note>
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If you want your <path>/tmp</path> to reside on a separate partition, be sure to
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change its permissions after mounting: <c>chmod 1777 /mnt/gentoo/tmp</c>. This
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also holds for <path>/var/tmp</path>.
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</note>
|
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<p>
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Finally we have to create the <path>/dev</path> files in our new home, which is
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needed during the bootloader installation. This could be done by "bind"-mapping
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the <path>/dev</path>-filesystem from the LiveCD:
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</p>
|
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<pre caption="Bind-mounting the /dev-filesystem">
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# <i>mkdir /mnt/gentoo/dev</i>
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# <i>mount -o bind /dev /mnt/gentoo/dev</i>
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</pre>
|
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<p>
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We will also have to mount the proc filesystem (a virtual interface with the
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kernel) on <path>/proc</path>. But first we will need to place our files on the partitions.
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</p>
|
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|
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<p>
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Continue with <uri link="?part=1&chap=5">Installing the Gentoo
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| 491 |
Installation Files</uri>.
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| 492 |
</p>
|
| 493 |
|
| 494 |
</body>
|
| 495 |
</section>
|
| 496 |
</sections>
|
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