Ext 2 to Ext4 difference

Ext2, Ext3, and Ext4 are three different versions of the extended file system (Ext), which is the default file system for many Linux distributions. Here are the key differences between Ext2, Ext3, and Ext4: Ext2: Ext2 was the first version of the extended file system. It provided basic features for managing files and directories but lacked features such as journaling. Without journaling, file system consistency in the event of a crash or power failure depended on time-consuming file system checks (fsck) during boot. It had limitations in terms of maximum file and partition sizes. Ext3: Ext3 was developed to address the lack of journaling in Ext2. It introduced journaling, which improved file system consistency and reduced the need for lengthy fsck operations after crashes or power failures. With journaling, Ext3 offered faster recovery times and improved reliability compared to Ext2. Ext3 maintained backward compatibility with Ext2, allowing Ext2 file systems to be upgraded to Ext3 without data loss. It still had limitations regarding maximum file and partition sizes, though these were improved compared to Ext2. Ext4: Ext4 is the latest version of the extended file system and offers several significant improvements over Ext3. It provides support for larger file systems and files, with maximum file size increased to 16 terabytes and maximum volume size to 1 exabyte. Ext4 also improves performance through various enhancements such as delayed allocation, extent-based allocation, and multiblock allocation. It includes support for extents, which replaces the traditional block mapping scheme and reduces metadata overhead for large files. Ext4 offers faster file system checks (fsck) and better scalability by using multiple block groups concurrently. It introduced other features like online defragmentation, improved timestamps, and sub-directory scalability. Ext4 maintains backward compatibility with Ext3 and allows for an in-place upgrade from Ext3 to Ext4 without data migration. In summary, each version of the extended file system introduced improvements in terms of reliability, performance, scalability, and feature set. Ext4 represents the most advanced version, offering significant enhancements over both Ext2 and Ext3, including support for larger file and partition sizes, improved performance, and new features like extents.