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<?xml version='1.0' encoding="UTF-8"?>
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<!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/handbook/hb-install-filesystems.xml,v 1.10 2012/04/22 10:59:41 swift Exp $ -->
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<!DOCTYPE included SYSTEM "/dtd/guide.dtd">
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<included>
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<version>9</version>
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<date>2012-04-22</date>
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<section id="filesystemsdesc">
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<title>Filesystems</title>
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<body>
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<p test="contains('x86 Alpha',func:keyval('arch'))">
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The Linux kernel supports various filesystems. We'll explain ext2, ext3, ext4,
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ReiserFS, XFS and JFS as these are the most commonly used filesystems on Linux
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systems.
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</p>
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<p test="func:keyval('arch')='IA64'">
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The Linux kernel supports various filesystems. We'll explain vfat, ext2, ext3,
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ext4, ReiserFS, XFS and JFS as these are the most commonly used filesystems on
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Linux systems.
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</p>
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<p test="func:keyval('arch')='AMD64'">
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Several filesystems are available. Some of them are found stable on the amd64
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architecture, others aren't. The following filesystems are found to be stable:
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ext2, ext3, ext4 and XFS. JFS and ReiserFS may work but need more testing. If
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you're really adventurous you can try the other filesystems.
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</p>
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<p test="func:keyval('arch')='arm'">
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Several filesystems are available. Some of them are found stable on the arm
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architecture, others aren't. ext2, ext3 and ext4 are found to be stable. JFS,
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XFS and ReiserFS may work but need more testing. If you're really adventurous
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you can try the other filesystems.
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</p>
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<p test="func:keyval('arch')='HPPA'">
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Several filesystems are available. Ext2, ext3, ext4, XFS and reiserfs are found
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stable on the HPPA architecture. The others are very experimental.
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</p>
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<p test="func:keyval('arch')='MIPS'">
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Several filesystems are available. ReiserFS, EXT2, EXT3 and EXT4 are found
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stable on the MIPS architectures, others are experimental.
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</p>
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<p test="func:keyval('arch')='PPC'">
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Several filesystems are available for use on the PowerPC architecture including
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ext2, ext3, ReiserFS and XFS, each with their strengths and faults.
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</p>
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<note test="func:keyval('arch')='PPC64'">
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Several filesystems are available. ext2, ext3 and ReiserFS support is built in
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the Installation CD kernels. JFS and XFS support is available through kernel
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modules.
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</note>
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<p test="func:keyval('arch')='SPARC'">
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Several filesystems are available, some are known to be stable on the
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SPARC architecture. Ext2, ext3 and ext4, for example, are known to work well.
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Alternate filesystems may not function correctly.
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</p>
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<note test="func:keyval('arch')='Alpha'">
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<c>aboot</c> only supports booting from <b>ext2</b> and <b>ext3</b>
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partitions.
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</note>
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</body>
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<body>
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<p test="func:keyval('arch')='IA64'">
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<b>vfat</b> is the MS-DOS filesystem, updated to allow long filenames. It is
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also the only filesystem type that the EFI firmware on ia64 systems
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understands. The boot partition on ia64 systems should always be vfat, but for
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your data partitions you should use one of the other filesystems listed below.
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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. If you intend to install Gentoo on a
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very small disk (less than 4GB), then you'll need to tell ext2 to reserve enough
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inodes when you create the filesystem. The <c>mke2fs</c> application uses the
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"bytes-per-inode" setting to calculate how many inodes a file system should have.
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By running <c>mke2fs -T small /dev/<device></c> the number of inodes will
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generally quadruple for a given file system as its "bytes-per-inode" reduces from
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one every 16kB to one every 4kB. You can tune this even further by using
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<c>mke2fs -i <ratio> /dev/<device></c>.
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</p>
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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. It uses an HTree index that enables high
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performance in almost all situations. In short, ext3 is a very good and
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reliable filesystem. Ext3 is the recommended all-purpose all-platform
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filesystem. If you intend to install Gentoo on a
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very small disk (less than 4GB), then you'll need to tell ext3 to reserve enough
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inodes when you create the filesystem. The <c>mke2fs</c> application uses the
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"bytes-per-inode" setting to calculate how many inodes a file system should have.
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By running <c>mke2fs -j -T small /dev/<device></c> the number of inodes will
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generally quadruple for a given file system as its "bytes-per-inode" reduces from
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one every 16kB to one every 4kB. You can tune this even further by using
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<c>mke2fs -j -i <ratio> /dev/<device></c>.
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</p>
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<p test="contains('x86 Alpha MIPS AMD64 arm IA64 SPARC HPPA',func:keyval('arch'))">
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<b>ext4</b> is a filesystem created as a fork of ext3 bringing new features,
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performance improvements and removal of size limits with moderate changes
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to the on-disk format. It can span volumes up to 1 EB and with maximum file
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size of 16 TB. Instead of the classic ext2/3 bitmap block allocation ext4 uses
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<uri link="http://en.wikipedia.org/wiki/Extent_%28file_systems%29">extents</uri>,
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which improve large file performance and reduce fragmentation. Ext4 also provides
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more sophisticated block allocation algorithms (delayed allocation and multiblock
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allocation) giving the filesystem driver more ways to optimise the layout of data
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on the disk. The ext4 filesystem is a compromise between production-grade code
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stability and the desire to introduce extensions to an almost decade old
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filesystem.
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</p>
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</body>
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<body test="not(func:keyval('arch')='SPARC')">
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<p test="not(func:keyval('arch')='PPC')">
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<b>JFS</b> is IBM's high-performance journaling filesystem. JFS is a light,
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fast and reliable B+tree-based filesystem with good performance in various
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conditions.
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</p>
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<p>
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<b>ReiserFS</b> is a B+tree-based journaled filesystem that has good overall
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performance, especially when dealing with many tiny files at the cost of more
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CPU cycles. ReiserFS appears to be less maintained than other filesystems.
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</p>
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<p>
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<b>XFS</b> is a filesystem with metadata journaling which comes with a robust
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feature-set and is optimized for scalability. XFS seems to be less forgiving to
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various hardware problems.
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</p>
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</body>
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</section>
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</included>
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