From the website: e4rat ("Ext4 - Reducing Access Times") is a toolset to accelerate the boot process as well as application startups. Through physical file realloction e4rat eliminates both seek times and rotational delays. This leads to a high disk transfer rate.
Committed to Sunrise, waiting for review: http://overlays.gentoo.org/proj/sunrise/browser/sunrise/sys-fs/e4rat +EBUILD, InOverlay, please.
Moved to portage. Thank you