Newbies What Next ? News Forums Calendar


News Sections
General News (3987/0)
Reviews (636/0)
Press Releases (465/0)
Distributions (197/0)
Software (907/0)
Hardware (537/0)
Security (192/0)
Tutorials (356/0)
Off Topic (181/0)

User Functions


Don't have an account yet? Sign up as a New User

There are no upcoming events



The ex4, or fourth extended file system, is a journailing file system for Linux which evolved from ext3. It is marked stable in Linux kernel 2.6.28.

ext4 adds many notable features particularly extents - a single descriptor for a range of contiguous blocks, as opposed to the traditional block mapping scheme used by ext2 and ext3. This represents an efficient way to represent large files, as well as utilising CPU more efficiently, and with fewer metadata IOs. This also makes for quicker file system checks, which becomes more beneficial as the file system grows in size.


Free to download



Mingming Cao, Andreas Dilger, Alex Zhuravlev (Tomas), Dave Kleikamp, Theodore Ts'o, Eric Sandeen, others


System Requirements

Support Sites:
Wiki, FAQ, Kernel Newbies

Selected Reviews:

Features include:

  • Extended attribute blocks and large inodes†
  • Extent-based disk format
  • Online Defragmentation
  • Online filesystem resize reservations
  • Hash-indexed directories
  • Journal file/device present
  • File type in directory entries
  • Journal recovery required
  • Files allocated with extent format
  • Support for more than 2^32 filesystem blocks
  • Flexible block group metadata location
  • Reduced block group backups
  • Reduced superblock backups
  • Files larger than 2GiB in size
  • Group descriptor checksums and sparse inode table
  • Over 32000 subdirectories
  • Inode-features
    • Larger inodes
    • Inode reservation
    • Nanosecond timestamps and creation time†
  • Files larger than 2TiB in size
  • Journal checksumming - checksums the journal data to know if the journal blocks are failing or corrupted
  • Option to turn off journaling
  • Persistent preallocation
  • Backward compatible with ext2 and ext3
  • Allocation schemes:
    • Persistent pre-allocation
    • Delayed allocation
    • Multi-block allocation
    • Stripe-aware allocation
  • Extended attributes
  • Quota journaling
  • Implements discard/TRIM

Return to Journaling File Systems Home Page

Bookmark and Share

Last Updated Monday, May 05 2014 @ 03:10 AM EDT

We have written a range of guides highlighting excellent free books for popular programming languages. Check out the following guides: C, C++, C#, Java, JavaScript, CoffeeScript, HTML, Python, Ruby, Perl, Haskell, PHP, Lisp, R, Prolog, Scala, Scheme, Forth, SQL, Node.js (new), Fortran (new), Erlang (new), Pascal (new), and Ada (new).

Group Tests
100 Essential Apps
All Group Tests

Top Free Software
5 Office Suites
3 Lean Desktops
7 Document Processors
4 Distraction Free Tools
9 Project Management
4 Business Solutions
9 Groupware Apps
14 File Managers
10 Databases
21 Backup Tools
21 Productivity Tools
5 Note Taking Apps
9 Terminal Emulators
21 Financial Tools
5 Bitcoin Clients
21 Text Editors
21 Video Emulators
21 Home Emulators
42 Graphics Apps
6 CAD Apps
42 Scientific Apps
10 Web Browsers
42 Email Apps
12 Instant Messaging
10 IRC Clients
7 Twitter Clients
12 News Aggregators
11 VoIP Apps
42 Best Games
9 Steam Games
42 Audio Apps
5 Music Streaming
42 Video Apps
5 YouTube Tools
80 Security Apps
9 System Monitoring
8 Geometry Apps
Free Console Apps
14 Multimedia
4 Audio Grabbers
9 Internet Apps
3 HTTP Clients
5 File Managers
8 Compilers
9 IDEs
9 Debuggers
7 Revision Control Apps
6 Doc Generators
Free Web Software
21 Web CMS
14 Wiki Engines
8 Blog Apps
6 eCommerce Apps
5 Human Resource Apps
10 ERP
10 CRM
6 Data Warehouse Apps
8 Business Intelligence
6 Point-of-Sale

Other Articles
Migrating from Windows
Back up your data
20 Free Linux Books
24 Beginner Books
12 Shell Scripting Books

Older Stories
Monday 03/09
  • Raspberry Pi 2: Raspbian (ARMv6) v Linaro (ARMv7) (0)

  • Friday 03/06
  • Raspberry Pi 2 review (0)

  • Sunday 02/22
  • Chess in a Few Bytes (0)
  • Learn the Art of Computer Programming With These Great Free Beginner Books (2)
  • CD Audio Grabbers (0)

  • Monday 01/19
  • fitlet is a tiny fanless PC full of openness (0)

  • Sunday 01/18
  • MintBox Mini gives Linux users a pocket-sized PC (0)
  • 6 Invaluable Assembly Books (0)

  • Wednesday 01/14
  • Why Mac users donít switch to Linux (0)
  • MIPS Creator CI20 review (0)

  • Vote

    What Linux distribution do you run on your main computer?

    667 votes | 3 comments

    Built with GeekLog and phpBB
    Comments to the webmaster are welcome
    Copyright 2009 - All rights reserved