Ext4 to be standard for Fedora 11, Btrfs also included
According to current plans, version 11 of Fedora, which is expected to arrive in late May, will use Ext4 as its standard file system. That's what the Fedora Engineering Steering Committee (FESCo) recently decided, following a heated discussion in an IRC meeting. If however Ext3's successor encounters big problems with the pre-release versions of Fedora 11, the developers will dump that plan and revert to Ext3.
So the Fedora Project is going one step beyond Ubuntu version 9.04 (Jaunty Jackalope), which as things currently stand will offer Ext4 as an install time option, though the installer will still use Ext3 as its default file system. The same was true of Fedora 9 and 10: the "ext4" parameter needed to be used when booting up the installation media, in order to enable that file system in the installer. Ext4 was still experimental when Fedora 10 was released.
After the recent acceptance of Btrfs into the main Linux development tree, chosen by some well known Linux file system developers as the "next generation filesystem" for Linux, the Fedora developers didn't wait and have already included support for Btrfs in Fedora Rawhide. So now, users of the Fedora development tree, which is updated virtually daily, can already play around with this still experimental file system, without having to grapple with compiling the kernel and suitable user space applications.
The developers have already extended the Fedora installer itself with support for Btrfs, though it is not yet mature and in a brief test by heise open, failed to work. That will probably also be the case with the alpha version of Fedora 11, based on Rawhide, which is now being prepared by the project for a launch on the 3rd of February. Just as with Ext4 under Fedora 9 and 10, users have to enable experimental support for Btrfs in the Fedora installer by setting a boot parameter. The developers have shown a sense of humour by initially assigning "icantbelieveitsnotbtr" as the command-line argument to activate Btrfs support.