Grub Legacy vs Grub 2

GRand Unified Boot System

Essentially, Grub Legacy is easy to reconfigure by just changing a single file. Grub 2 has several config files, then once you’ve changed them, you have to run a script to update the cfg file that grub2 reads in order for the changes to take effect.

Legacy config is simple:

/boot/grub/menu.lst « how you change how the system boots, unique to grub legacy

Grub2 config:

/etc/default/grub « one of the config files

grub2-mkconfig -o /path/to/grub.cfg (probably /etc/grub2/grub.cfg)

Hafta’ change config file, then run the mkconfig to regenerate the grub.cfg, then your changes take effect.

OS differences

Ubuntu

  • grub2 since 2009
  • backward compatible
  • grub2 stuff in /boot/grub/grub.cfg

Enterprise 6 (centos, rhel, whatev)

  • grub legacy
  • no grub2 tools

Enterprise 7 (centos, rhel, whatev)

  • grub2
  • no backwards compatibility
  • /boot/grub2/