The ext4 or fourth extended filesystem is a journaled file system developed as the successor to ext3. It was born as a series of backwards-compatible extensions to add to ext3 64-bit storage limits and other performance improvements . However, other Linux kernel developers opposed accepting extensions to ext3 for stability reasons, and proposed to fork the source code of ext3, rename it as ext4, and do all the development there, without affecting the current ext3 users. This proposal was accepted, and on June 28, 2006 Theodore Ts'o, the ext3 maintainer, announced the new plan of development for ext4. A preliminary development snapshot of ext4 was included in version 2.6.19 of the Linux kernel. On Oct 11, 2008, the patches that mark ext4 as stable code were merged in the Linux 2.6.28 source code repositories, denoting the end of the development phase and recommending ext4 adoption. Kernel 2.6.28, containing the ext4 filesystem, was finally released on December 25, 2008....
Installing/Switching to Ext4
Please read Create_an_Ext4_Partition for information about creating an Ext4 partition