Documentation< Previous | Contents | Next >
7.6.8.1. Customizing the Boot and Shutdown Scripts
The LFS boot scripts boot and shut down a system in a fairly efficient manner, but there are a few tweaks that you can make in the rc.site file to improve speed even more and to adjust messages according to your preferences. To do this, adjust the settings in the /etc/sysconfig/rc.site file above.
• During the boot script udev, there is a call to udev settle that requires some time to complete. This time may or may not be required depending on devices present in the system. If you only have simple partitions and a
single ethernet card, the boot process will probably not need to wait for this command. To skip it, set the variable OMIT_UDEV_SETTLE=y.
• The boot script udev_retry also runs udev settle by default. This command is only needed by default if the / var directory is separately mounted. This is because the clock needs the file /var/lib/hwclock/adjtime. Other customizations may also need to wait for udev to complete, but in many installations it is not needed. Skip the command by setting the variable OMIT_UDEV_RETRY_SETTLE=y.
• By default, the file system checks are silent. This can appear to be a delay during the bootup process. To turn on the fsck output, set the variable VERBOSE_FSCK=y.
• When rebooting, you may want to skip the filesystem check, fsck, completely. To do this, either create the file / fastboot or reboot the system with the command /sbin/shutdown -f -r now. On the other hand, you can force all file systems to be checked by creating /forcefsck or running shutdown with the -F parameter instead of - f.
Setting the variable FASTBOOT=y will disable fsck during the boot process until it is removed. This is not recommended on a permanent basis.
• Normally, all files in the /tmp directory are deleted at boot time. Depending on the number of files or directories present, this can cause a noticeable delay in the boot process. To skip removing these files set the variable SKIPTMPCLEAN=y.
• During shutdown, the init program sends a TERM signal to each program it has started (e.g. agetty), waits for a set time (default 3 seconds), and sends each process a KILL signal and waits again. This process is repeated in the sendsignals script for any processes that are not shut down by their own scripts. The delay for init can be set by passing a parameter. For example to remove the delay in init, pass the -t0 parameter when shutting down or rebooting (e.g. /sbin/shutdown -t0 -r now). The delay for the sendsignals script can be skipped by setting the parameter KILLDELAY=0.