Appendix E. The GRUB Boot Loader

When a computer running Linux is turned on, the operating system is loaded into memory by a special program called a boot loader. A boot loader usually exists on the system's primary hard drive (or other media device) and has the sole responsibility of loading the Linux kernel with its required files or (in some cases) other operating systems into memory.

E.1. Boot Loaders and System Architecture

Each architecture capable of running Red Hat Enterprise Linux uses a different boot loader. The following table lists the boot loaders available for each architecture:

Table E.1. Boot Loaders by Architecture

Architecture Boot Loaders
AMD AMD64 GRUB
IBM Power Systems yaboot
IBM System z z/IPL
x86 GRUB
This appendix discusses commands and configuration options for the GRUB boot loader included with Red Hat Enterprise Linux for the x86 architecture.

Important — Supported file systems

The /boot and / (root) partition in Red Hat Enterprise Linux 6.6 can only use the ext2, ext3, and ext4 (recommended) file systems. You cannot use any other file system for this partition, such as Btrfs, XFS, or VFAT. Other partitions, such as /home, can use any supported file system, including Btrfs and XFS (if available). See the following article on the Red Hat Customer Portal for additional information: https://access.redhat.com/solutions/667273.