Contents of /xml/htdocs/doc/en/handbook/hb-install-filesystems.xml

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Bug #489782 - Duplicate instructions for ext2, ext3 and possibly ext4 now separate

1 <?xml version='1.0' encoding="UTF-8"?>
2 <!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/handbook/hb-install-filesystems.xml,v 1.13 2013/02/23 18:38:22 swift Exp $ -->
3 <!DOCTYPE included SYSTEM "/dtd/guide.dtd">
5 <included>
7 <version>12</version>
8 <date>2013-12-17</date>
10 <section id="filesystemsdesc">
11 <title>Filesystems</title>
12 <body>
14 <p test="contains('x86 Alpha',func:keyval('arch'))">
15 The Linux kernel supports various filesystems. We'll explain ext2, ext3, ext4,
16 ReiserFS, XFS and JFS as these are the most commonly used filesystems on Linux
17 systems.
18 </p>
20 <p test="func:keyval('arch')='IA64'">
21 The Linux kernel supports various filesystems. We'll explain vfat, ext2, ext3,
22 ext4, ReiserFS, XFS and JFS as these are the most commonly used filesystems on
23 Linux systems.
24 </p>
26 <p test="func:keyval('arch')='AMD64'">
27 Several filesystems are available. Some of them are found stable on the amd64
28 architecture, others aren't. The following filesystems are found to be stable:
29 ext2, ext3, ext4 and XFS. JFS and ReiserFS may work but need more testing. If
30 you're really adventurous you can try the other filesystems.
31 </p>
33 <p test="func:keyval('arch')='arm'">
34 Several filesystems are available. Some of them are found stable on the arm
35 architecture, others aren't. ext2, ext3 and ext4 are found to be stable. JFS,
36 XFS and ReiserFS may work but need more testing. If you're really adventurous
37 you can try the other filesystems.
38 </p>
40 <p test="func:keyval('arch')='HPPA'">
41 Several filesystems are available. Ext2, ext3, ext4, XFS and reiserfs are found
42 stable on the HPPA architecture. The others are very experimental.
43 </p>
45 <p test="func:keyval('arch')='MIPS'">
46 Several filesystems are available. ReiserFS, EXT2, EXT3 and EXT4 are found
47 stable on the MIPS architectures, others are experimental.
48 </p>
50 <p test="func:keyval('arch')='PPC'">
51 Several filesystems are available for use on the PowerPC architecture including
52 ext2, ext3, ext4, ReiserFS and XFS, each with their strengths and faults.
53 </p>
55 <note test="func:keyval('arch')='PPC64'">
56 Several filesystems are available. ext2, ext3, ext4 and ReiserFS support is built in
57 the Installation CD kernels. JFS and XFS support is available through kernel
58 modules.
59 </note>
61 <p test="func:keyval('arch')='SPARC'">
62 Several filesystems are available, some are known to be stable on the
63 SPARC architecture. Ext2, ext3 and ext4, for example, are known to work well.
64 Alternate filesystems may not function correctly.
65 </p>
67 <note test="func:keyval('arch')='Alpha'">
68 <c>aboot</c> only supports booting from <b>ext2</b> and <b>ext3</b>
69 partitions.
70 </note>
72 </body>
73 <body>
75 <p test="func:keyval('arch')='IA64'">
76 <b>vfat</b> is the MS-DOS filesystem, updated to allow long filenames. It is
77 also the only filesystem type that the EFI firmware on ia64 systems
78 understands. The boot partition on ia64 systems should always be vfat, but for
79 your data partitions you should use one of the other filesystems listed below.
80 </p>
82 <p>
83 <b>ext2</b> is the tried and true Linux filesystem but doesn't have metadata
84 journaling, which means that routine ext2 filesystem checks at startup time can
85 be quite time-consuming. There is now quite a selection of newer-generation
86 journaled filesystems that can be checked for consistency very quickly and are
87 thus generally preferred over their non-journaled counterparts. Journaled
88 filesystems prevent long delays when you boot your system and your filesystem
89 happens to be in an inconsistent state.
90 </p>
92 <p>
93 <b>ext3</b> is the journaled version of the ext2 filesystem, providing metadata
94 journaling for fast recovery in addition to other enhanced journaling modes like
95 full data and ordered data journaling. It uses an HTree index that enables high
96 performance in almost all situations. In short, ext3 is a very good and
97 reliable filesystem.
98 </p>
100 <p test="contains('x86 Alpha MIPS AMD64 arm IA64 SPARC HPPA PPC PPC64',func:keyval('arch'))">
101 <b>ext4</b> is a filesystem created as a fork of ext3 bringing new features,
102 performance improvements and removal of size limits with moderate changes
103 to the on-disk format. It can span volumes up to 1 EB and with maximum file
104 size of 16 TB. Instead of the classic ext2/3 bitmap block allocation ext4 uses
105 <uri link="http://en.wikipedia.org/wiki/Extent_%28file_systems%29">extents</uri>,
106 which improve large file performance and reduce fragmentation. Ext4 also provides
107 more sophisticated block allocation algorithms (delayed allocation and multiblock
108 allocation) giving the filesystem driver more ways to optimise the layout of data
109 on the disk. The ext4 filesystem is a compromise between production-grade code
110 stability and the desire to introduce extensions to an almost decade old
111 filesystem. Ext4 is the recommended all-purpose all-platform filesystem.
112 </p>
114 <p>
115 If you intend to install Gentoo on a very small disk (less than 4GB), then you'll
116 need to tell ext2, ext3 or ext4 (if available) to reserve enough inodes when you
117 create the filesystem. The <c>mke2fs</c> application uses the "bytes-per-inode"
118 setting to calculate how many inodes a file system should have. By running
119 <c>mke2fs -T small /dev/&lt;device&gt;</c> (ext2) or <c>mke2fs -j -T small
120 /dev/&lt;device&gt;</c> (ext3/ext4) the number of inodes will generally
121 quadruple for a given file system as its "bytes-per-inode" reduces from
122 one every 16kB to one every 4kB. You can tune this even further by using
123 <c>mke2fs -i &lt;ratio&gt; /dev/&lt;device&gt;</c> (ext2) or <c>mke2fs -j
124 -i &lt;ratio&gt; /dev/&lt;device&gt;</c> (ext3/ext4).
125 </p>
127 </body>
128 <body test="not(func:keyval('arch')='SPARC')">
130 <p test="not(func:keyval('arch')='PPC')">
131 <b>JFS</b> is IBM's high-performance journaling filesystem. JFS is a light,
132 fast and reliable B+tree-based filesystem with good performance in various
133 conditions.
134 </p>
136 <p>
137 <b>ReiserFS</b> is a B+tree-based journaled filesystem that has good overall
138 performance, especially when dealing with many tiny files at the cost of more
139 CPU cycles. ReiserFS appears to be less maintained than other filesystems.
140 </p>
142 <p>
143 <b>XFS</b> is a filesystem with metadata journaling which comes with a robust
144 feature-set and is optimized for scalability. XFS seems to be less forgiving to
145 various hardware problems.
146 </p>
148 </body>
149 </section>
150 </included>

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