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CONFIG_EXT4_FS: The Extended 4 (ext4) filesystem

General informations

The Linux kernel configuration item CONFIG_EXT4_FS:

Help text

This is the next generation of the ext3 filesystem.

Unlike the change from ext2 filesystem to ext3 filesystem, the on-disk format of ext4 is not forwards compatible with ext3; it is based on extent maps and it supports 48-bit physical block numbers. The ext4 filesystem also supports delayed allocation, persistent preallocation, high resolution time stamps, and a number of other features to improve performance and speed up fsck time. For more information, please see the web pages at

The ext4 filesystem supports mounting an ext3 filesystem; while there are some performance gains from the delayed allocation and inode table readahead, the best performance gains require enabling ext4 features in the filesystem using tune2fs, or formatting a new filesystem as an ext4 filesystem initially. Without explicit enabling of ext4 features, the on disk filesystem format stays fully backward compatible.

To compile this file system support as a module, choose M here. The module will be called ext4.

If unsure, say N.



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