In 2009, version 5.4 of 64-bit Red Hat Enterprise Linux (RHEL) Linux distribution contained the necessary kernel support for the creation and usage of XFS file systems, but lacked the corresponding command-line tools. The tools available from CentOS could operate for that purpose, and Red Hat also provided them to RHEL customers on request. RHEL 6.0, released in 2010, includes XFS support for a fee as part of Red Hat's "scalable file system add-on". Oracle Linux 6, released in 2011, also includes an option for using XFS.