What is EXT3?

The ext3 or third extended file system is a journalled file system that is coming into increasing use among users of the Linux operating system. It is the default file system for the Red Hat, Fedora and Debian Linux distributions. Why to migrate from ext2 to ext3? Four main reasons: availability, data integrity, speed, and easy transition.

Although its performance and scalability is less attractive than many of its competitors such as ReiserFS and XFS, it does have the significant advantage in that it allows in-place upgrades from the popular ext2 file system without having to backup and restore data.

Over its predecessor, the ext3 file system adds:

A journal
H-tree (hashed tree) directory indexes
In-directory file types

Without these, any ext3 file system is also a valid ext2 file system. This has allowed well-tested and mature file system maintenance utilities (like fsck) for maintaining and repairing ext2 file systems to also be used with ext3 without major changes. It also makes conversion between the two file systems (both forward to ext3 and backward to ext2) straightforward.

There are three levels of journalling available in the Linux implementation of ext3:

Journal, where both metadata and file contents are written to the journal before being committed to the main file system. This improves reliability at a performance penalty because all data has to be written twice.

Writeback, where metadata is journalled but file contents are not. This is faster, but introduces the hazard of out-of-order writes where, for example, files being appended to during a crash may gain a tail of garbage on the next mount.

Ordered, as with writeback, but forces file contents to be written after its associated metadata is. This is thought to be an acceptable compromise between reliability and performance, and hence is the default.

Boasting higher reliability and better performance, EXT3 indeed is the right choice if you still use the older EXT2 file system. While no matter how reliable EXT3 it is, lots of people still have a bad experience of losing data for some reasons like accidental deletion, format or partition loss or corruption. At this time, professional and comprehensive data recovery software must be a saver to recover lost files from EXT3 file system easily and quickly for all kinds of lost files like word or office files, pictures, photos or video.

EASEUS Data Recovery Wizard Professional Edition is just the right one for EXT 2/EXT3 and FAT and NTFS partition recovery. Download it now and refer to here for how-to recover lost files from EXT2/EXT3/FAT/NTFS partition.

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