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Crash Testing ext4 on Ubuntu 9.04

Apr 19, 2009, 20:02 (0 Talkback[s])

[ Thanks to Mike Weber for this link. ]

"What is ext4?
The ext4 file system is a journaling file system which is a branch of ext3. Ext3 has been so valuable in terms of stability and usability to Linux that the developers decided to fork ext3 to ext4 instead of incorporating the features of ext into ext3. Those features include 64-bit storage limits and performance boosts. The 2.6.28 Kernel included ext4 as stable code.

Advantages of ext4.
The advantages of ext4 are two. Ext4 has increased filesystem support for volumes up to 1 exabyte, with files up to 16 terabytes. In addition, ext4 has increased performance. Currently, ext supports 16 terabyte filesystem and 2 terabyte file size.

"Ext4 uses extents, which are a contiguous range of physical blocks on the hard drive. The key word here is contiguous, as you can see in the illustration the blocks are close together. The advantage is large file size performance and the reduction of fragmentation because your data is placed in a more centralized area. A extent can be up to 128MB of contiguous space with 4KB block size. If you choose to use extents in ext4 you will not be able to go backwards to ext3 as the extents are not compatible with ext3."

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