ext4: The Fourth Extended Filesystem

The ext4 file system is to be the successor to the ext3 journaled file system and will be available as an optional file system in the next release of Ubuntu, Ubuntu 9.04.

The ext4 file system is now, as of December 25, 2008, released as stable and can be used as the dominant file system without fear of data lose…well, to be more clear I mean no more fear than any other “stable” file system. 😛

Ext4 is capable of supporting hard drives up to 1 exabyte in size. To put that in terms you might understand more easily, that’s 1,073,741,824 gigabytes!

Also, new with ext4 is an increased maximum file size! Files can now be created up to an impressive size of 16 tebibytes compared to 2 tebibytes in ext3! That’s 16,384 gigabytes!

Support for the ext4 file system begins with Kernel 2.6.28, so previous versions will be incompatible and unable to mount an ext4 volume.

As computer processors continually increase in speed and performance, it becomes increasingly important that timestamps are accurate and very accurate at that. The ext4 file system will store timestamps for created or modified files down to the nanosecond!

This means that creating files very quickly will result in more unique timestamps, thus increasing the ability to compare new and old files down to the nanosecond! This could be very important in the future for tasks such as synchronization!

If you’re interested in seeing better performance during file system check, reading and writing files then you’ll want to give Ubuntu 9.04 Jaunty Jackalope or Fedora 11 a try when they are released!

If you’re interested in seeing some performance benchmarks, then I’ve already collected a few here for you to take a look at: