grub 2.0配置

grub2.0启动盘安装:

grub-install --target=i386-pc /dev/sdx

Note:
/dev/sda 只是示例.
--target=i386-pc指示grub-install是为使用BIOS的系统安装. 推荐一直标明这点以防混淆.

安装到U盘
假设 U盘的第一个分区是 FAT32，其分区是/dev/sdy1.(安装前要注意备份grub.cfg)

# mkdir -p /mnt/usb
# mount /dev/sdy1 /mnt/usb
# grub-install --target=i386-pc --debug --boot-directory=/mnt/usb/boot /dev/sdy
# grub-mkconfig -o /mnt/usb/boot/grub/grub.cfg

下面是一些grub.cfg引导示例:

#grub2启动Linux 2.6
menuentry "Linux 2.6.31-10-generic" {
	set quiet=1
	insmod ext2
	set root=(hd0,8)
	search --no-floppy --fs-uuid --set 2d61e5f9-1d2a-4167-a6f1-b991ba00878b
	#这句与set root=(hd0,8)效果一样，可删除其一，二者不一致以这句为准
	linux /boot/vmlinuz-2.6.31-10-generic root=UUID=2d61e5f9-1d2a-4167-a6f1-b991ba00878b ro quiet splash
	#不喜欢看到一长串的， roo=UUID=***可用root=/dev/sda8(/分区的分区号)代替
	initrd /boot/initrd.img-2.6.31-10-generic
}
#grub2启动Arch Linux
menuentry 'Arch Linux' {
	load_video
	set gfxpayload=keep
	insmod gzio
	insmod part_msdos
	insmod ext2
	set root='hd0,msdos1'

	echo    '载入 Linux linux ...'
	linux   /vmlinuz-linux root=/dev/sda3 init=/usr/lib/systemd/systemd rw  quiet
	echo    '载入初始化内存盘...'
	initrd  /initramfs-linux.img
}

#grub2启动Windows XP
menuentry "Windows XP" {
	set root=(hd1,1)
	#这行不用应该也行
	drivemap -s (hd0) ${root}
	chainloader +1
}
menuentry "Windows XP" {
	insmod ntfs
	search --set=root --label WINDOWS_XP --hint hd0,msdos1
	ntldr /ntldr
}

#grub2启动软盘镜像
menuentry "Boot from DOS IMG" {
	linux16 /memdisk
	initrd16 /win98.img
}

#grub2启动光盘镜像
menuentry 'Boot Windows 8 PE ISO'{
	set root='(hd0,msdos1)'
	echo 'Loading Memdisk...'
	insmod memdisk
	linux16 /boot/memdisk iso raw
	echo 'Loading ISO...'
	initrd16 /boot/Win8PE.iso
}

下面是最简单的配置:

# Config file for GRUB - The GNU GRand Unified Bootloader
# /boot/grub/grub.cfg

# DEVICE NAME CONVERSIONS
#
#  Linux           Grub
# -------------------------
#  /dev/fd0        (fd0)
#  /dev/sda        (hd0)
#  /dev/sdb2       (hd1,2)
#  /dev/sda3       (hd0,3)
#

# Timeout for menu
set timeout=5

# Set default boot entry as Entry 0
set default=0

# (0) Arch Linux
menuentry "Arch Linux" {
  set root=(hd0,1)
  linux /vmlinuz-linux root=/dev/sda3 ro
  initrd /initramfs-linux.img
}

## (1) Windows
#menuentry "Windows" {
#  set root=(hd0,3)
#  chainloader +1
#}

grub2.0有很方便的工具，一般直接用工具生成配置文件:

grub-mkconfig -o /boot/grub/grub.cfg

从grub1.99转换为2.0的配置

title linux
	root (hd0,0)
	kernel /vmlinuz-linux_oldver root=/dev/sda3 init=/usr/lib/systemd/systemd rw quiet
	initrd /initrd_oldver.img

menuentry 'linux' {
	set root='hd0,msdos1'

	linux   /vmlinuz-linux_oldver root=/dev/sda3 init=/usr/lib/systemd/systemd rw quiet
	initrd  /initrd_oldver.img
}

制作grub2.0的启动映像:

grub-mkrescue -o grub.iso