Startup Configuration

This documents the boot process in Gentoo Linux.

Checking GRUB

• Checking GRUB can only be done visually or through a (v)KVM. Note that GRUB does not write to the filesystem when ran, only to the boot sectors of the hard drive. If GRUB boots on a vKVM, it means it is OK, even if the hardware is emulated inside the vKVM.

• Note that repartitioning a disk does not necessarily wipe out the bootloader (GRUB) which is installed in the Master Boot Record (MBR). To completely erase a previously installed bootloader:

dd if="/dev/zero" of="${HARD_DISK_DEVICE}" count="1" bs="2048"

Note that the previous command will destroy the partition table, so will destroy all data on the hard drive!

Obtaining a log of the boot messages

• This is actually difficult. dmesg will give you a log of the kernel messages, and emerging a log system (and activating it, you need to add the init script to a runlevel) will also give you some information. But getting a complete log of the init scripts messages is hard.

• You can still get some information by editing /etc/conf.d/rc, changing RC_BOOTLOG="yes" and emerging the package showconsole. The log file will be written to /var/log/boot.msg. But it will miss some parts of the boot process - that's normal.

udev activating services

• If udev is activating services you don't want (and possibly also loading kernel modules), try to change RC_COLDPLUG value in /etc/conf.d/rc (and possibly RC_HOTPLUG too).

Mounting filesystems

• Filesystems listed in /etc/fstab are either mounted by the localmount script, or if they are considered network filesystems, by the netmount script. The list of filesystems considered network are in the variable NET_FS_LIST, normally defined in /sbin/functions.sh. You can override it in /etc/conf.d/localmount and /etc/conf.d/netmount.