Add boot/shutdown script customization instructions

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@10016 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

1 files changed, 67 insertions, 0 deletions

diff --git a/chapter07/site.xml b/chapter07/site.xml
index 47b327eee..dcb2c5532 100644
--- a/chapter07/site.xml
+++ b/chapter07/site.xml
@@ -32,5 +32,72 @@
   <!-- Use role to fix a pdf generation problem -->
   <screen role="auto">&site;</screen>
 
+  <sect2>
+    <title>Customizing the Boot and Shutdown Scripts</title>
+
+    <para>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 accoring
+    to your preferences. To do this, adjust the settings in
+    the <filename>/etc/sysconfig/rc.site</filename> file above.</para>
+
+    <itemizedlist>
+
+    <listitem><para>During the boot script <filename>udev</filename>, there is
+    a call to <command>udev settle</command> 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.</para></listitem>
+
+    <listitem><para>The boot script <filename>udev_retry</filename> also runs
+    <command>udev settle</command> by default.  This command is only needed by
+    default if the <filename class='directory'>/var</filename> directory is
+    separately mounted.  This is because the clock needs the file
+    <filename>/var/lib/hwclock/adjtime</filename>.  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.
+    </para></listitem>
+
+    <listitem><para>By default, the file system checks are silent.  This can
+    appear to be a delay during the bootup process.  To turn on the
+    <command>fsck</command> output, set the variable VERBOSE_FSCK=y.
+    </para></listitem>
+
+    <listitem><para>When rebooting, you may want to skip the filesystem check,
+    <command>fsck</command>, completely.  To do this, either create the file
+    <filename>/fastboot</filename> or reboot the system with the command
+    <command>/sbin/shutdown -f -r now</command>.  On the other hand, you can
+    force all file systems to be checked by creating
+    <filename>/forcefsck</filename> or running <command>shutdown</command> with
+    the <parameter>-F</parameter> parameter instead of <parameter>-f</parameter>.  
+    </para>
+    
+    <para>Setting the variable FASTBOOT=y will disable <command>fsck</command>
+    during the boot process until it is removed.  This is not recommended 
+    on a permanent basis.</para></listitem>
+
+    <listitem><para>Normally, all files in the <filename
+    class='directory'>/tmp</filename> directory are deleted at boot time.
+    Depending on the number of files or directories present, this can cause a
+    noticible delay in the boot process.  To skip removing these files set the
+    variable SKIPTMPCLEAN=y.</para></listitem>
+
+    <listitem><para>During shutdown, the <command>init</command> 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 <command>sendsignals</command>
+    script for any processes that are not shut down by their own scripts.  The
+    delay for <command>init</command> can be set by passing a parameter.  For
+    example to remove the delay in <command>init</command>, pass the -t0
+    parameter when shutting down or rebooting (e.g.  <command>/sbin/shutdown
+    -t0 -r now</command>).  The delay for the  <command>sendsignals</command>
+    script can be skipped by setting the parameter
+    KILLDELAY=0.</para></listitem>
+
+    </itemizedlist>
+
+  </sect2>
+
 </sect1>