ext4 (fourth extended filesystem) is a journaling file system for Linux, developed as the successor to ext3.

May 30, 2023 · The first in a series of blogs aimed at providing an insight into the internal disk layout of an ext4 file system.

ext4 Filesystem General usage and on-disk artifacts writen by ext4. More documentation may be ported from the wiki as time permits. This should be considered the canonical source of information as the …

Dec 28, 2025 · This article explains what ext4 is, how it stores data on disk, how journaling protects your files, and — most importantly — how to inspect each structure yourself on a real Linux system.

The ext4 file system is a scalable extension of the ext3 file system. With Red Hat Enterprise Linux 7, it can support a maximum individual file size of 16 terabytes, and file systems to a maximum of 50 …

May 25, 2017 · Take a walk through EXT4's history, features, and optimal use, and learn how it differs from previous iterations of the EXT filesystem.

Deep dive into ext4 file system internals: block group layout, extent trees replacing indirect blocks, three journaling modes (journal/ordered/writeback), delayed allocation, and multi-block allocation.

Each mounted filesystem will have a directory in /sys/fs/ext4 based on its device name (i.e., /sys/fs/ext4/hdc or /sys/fs/ext4/dm-0). The files in each per-device directory are shown in table below.

Mar 6, 2026 · Even though the filesystem is now converted to ext4, all files that have been written before the conversion do not yet take advantage of the extent option of ext4, which will improve large file …

Aug 25, 2017 · This is a complete tutorial for understanding the basics of Linux ext4 file system.