doc/en/gentoo-x86-tipsntricks.xml

<?xml version='1.0' encoding="UTF-8"?>
<!DOCTYPE guide SYSTEM "/dtd/guide.dtd">
<!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/gentoo-x86-tipsntricks.xml,v 1.9 2004/09/22 21:57:14 neysx Exp $ -->

<guide link="/doc/en/gentoo-x86-tipsntricks.xml">
<title>Gentoo/x86 Installation Tips &amp; Tricks</title>
<author title="Author">
    <mail link="swift@gentoo.org">Sven Vermeulen</mail>
</author>

<abstract>
The Gentoo installation allows for very flexible approaches to the various
installation methods. As it is almost impossible to insert every single tip or
trick in the installation instructions this document tries to deal with all
submitted tips and tricks for reference purposes.
</abstract>

<license/>

<version>1.6</version>
<date>September 25, 2004</date>

<chapter>
<title>Introduction</title>
<section>
<title>Preliminary</title>
<body>

<p>
This document contains various tips and tricks for the Gentoo/x86 installation.
Most of them are discussed in a dense way - they are meant as an addendum to the
installation instructions and not as a replacement.
</p>

</body>
</section>
<section>
<title>Contents</title>
<body>

<p>
<b>Advanced Installations</b>
</p>

<ul>
  <li><uri link="#software-raid">Software RAID</uri></li>
  <li><uri link="#ata-raid-2.4">ATA RAID using 2.4 kernels</uri></li>
  <li><uri link="#livecd-kernel">Using the LiveCD kernel</uri></li>
</ul>

<p>
<b>Simplifying the Installation</b>
</p>

<ul>
  <li><uri link="#leave_terminal">Leaving the Terminal</uri></li>
</ul>

<p>
<b>Fixing Errors/Issues</b>
</p>

<ul>
  <li><uri link="#checking-disks">Extensive Testing of your Disks</uri></li>
  <li>
    <uri link="#recover">Recovering from a malfunctioning installation</uri>
  </li>
</ul>

</body>
</section>
</chapter>
<chapter>
<title>Advanced Installations</title>
<section id="software-raid">
<title>Software RAID</title>
<body>

<note>
If you are not known to software raid, please read the <uri
link="http://tldp.org/HOWTO/Software-RAID-HOWTO.html">Software-RAID-HOWTO</uri>.
</note>

<p>
Once you are booted from the LiveCD, load the appropriate RAID modules. For
instance, if you plan on using RAID-1:
</p>

<pre caption="Loading the RAID-1 module">
# <i>modprobe raid1</i>
</pre>

<p>
When you partition your disks, make sure that your partitions use <c>fd</c>
(Linux raid autodetect) as Partition Type instead of <c>83</c> (Linux native).
You can alter the partition type using the <c>t</c> command in <c>fdisk</c>.
</p>

<p>
After partitioning, create the <path>/etc/mdadm.conf</path> file (yes, indeed, 
on the LiveCD environment) using <c>mdadm</c>, an advanced tool for <uri 
link="http://www.linuxdevcenter.com/pub/a/linux/2002/12/05/RAID.html">RAID
management</uri>. For instance, to have your boot, swap and root partition 
mirrored (RAID-1) covering <path>/dev/sda</path> and <path>/dev/sdb</path>, 
you can use:
</p>

<pre caption="mdadm command example">
# <i>mdadm --create --verbose /dev/md0 --level=1 --raid-devices=2 /dev/sda1 /dev/sdb1</i>
# <i>mdadm --create --verbose /dev/md1 --level=1 --raid-devices=2 /dev/sda2 /dev/sdb2</i>
# <i>mdadm --create --verbose /dev/md2 --level=1 --raid-devices=2 /dev/sda3 /dev/sdb3</i>
</pre>

<p>
The Linux Software RAID driver will start creating the metadevices. You can see
its progress in <path>/proc/mdstat</path>. Wait until the metadevices are
completely finished before proceeding.
</p>

<p>
From now onwards, use <path>/dev/md0</path> for the boot partition,
<path>/dev/md1</path> for the swap partition and <path>/dev/md2</path> for the
root partition.
</p>

<p>
After mounting <path>/dev/md2</path> on <path>/mnt/gentoo</path>, don't forget
to copy over <path>/etc/mdadm.conf</path> to <path>/mnt/gentoo/etc</path>.
</p>

<p>
When you're configuring your kernel, make sure you have the appropriate RAID
support <e>in</e> your kernel and not as module. 
</p>

<p>
When installing extra tools, emerge <c>mdadm</c> as well. Note that this
isn't available on all LiveCDs so you might not be able to install Gentoo on a
Software RAID when using a networkless installation!
</p>

<p>
When configuring your bootloader, make sure it gets installed in the MBR of
<e>both</e> disks if you use mirroring. 
</p>

</body>
</section>
<section id="ata-raid-2.4">
<title>ATA RAID using 2.4 kernels</title>
<body>

<p>
Make sure you boot your LiveCD using the <c>doataraid</c> option. Once booted,
check the contents of <path>/dev/ataraid</path>. It should contain various
<path>disc*</path> directories for each harddisk available in the ATA RAID. An
entire disk is displayed as <path>disc</path> while partitions are
<path>part*</path>.
</p>

<p>
Write down the various <path>/dev/ataraid/disc*/*</path> device files that you
use to install Gentoo on. You will need to substitute the <path>/dev/hda</path>
examples in the installation with this path.
</p>

<p>
Before chrooting, bind-mount the <path>/dev</path> structure in the new
environment:
</p>

<pre caption="Bind-mounting /dev">
# <i>mount -o bind /dev /mnt/gentoo/dev</i>
</pre>

<p>
When configuring your kernel, make sure you enable support for your ATA RAID
chipset and options. For instance, a popular ATA RAID system is a <e>Promise
FastTrack built-in RAID</e> in which case you definitely need <c>Promise
FastTrack Options</c> built in into your kernel.
</p>

<p>
When configuring GRUB, you first have to create a GRUB bootdisk. This is not as
hard as you think. First install GRUB as you would, but when you come to the
part where GRUB is getting installed in the MBR, follow the following
instructions:
</p>

<pre caption="Creating a GRUB bootdisk">
# <i>cd /boot/grub</i>
# <i>dd if=stage1 of=/dev/fd0 bs=512 count=1</i>
# <i>dd if=stage2 of=/dev/fd0 bs=512 seek=1</i>
</pre>

<p>
You still need to write your <path>grub.conf</path> file. This is no different
from the installation instructions, just make sure that your <c>root=</c> points
to the ATA RAID device. 
</p>

<p>
After finishing the installation, boot with your GRUB bootdisk. You will be
greeted by a GRUB prompt. Now configure GRUB to boot from the ATA RAID device:
</p>

<pre caption="Installing GRUB on the ATA RAID">
grub&gt; root (hd0,x)
grub&gt; setup (hd0)
grub&gt; quit
</pre>

<p>
Now reboot (with the GRUB bootfloppy removed).
</p>

<p>
LILO users can safely use the instructions mentioned in the installation
instructions.
</p>

</body>
</section>
<section id="livecd-kernel">
<title>Using the LiveCD kernel</title>
<body>

<p>
If you don't want to compile a kernel yourself you can use the kernel from the
LiveCD and copy it to your system. When you come to the point that you're asked
to compile a kernel, go to another terminal (press Alt-F2) and log in with the
root password you've supplied at the beginning of the installation.
</p>

<p>
Copy over the kernel and modules to your Gentoo system:
</p>

<pre caption="Copying over the LiveCD kernel">
<comment>(${KN} is the kernel name, usually something like 'gentoo' or 'smp')</comment>
cdimage ~# <i>cp /mnt/cdrom/isolinux/${KN} /mnt/cdrom/isolinux/${KN}.gz /mnt/gentoo/boot</i>
cdimage ~# <i>mkdir -p /mnt/gentoo/lib/modules</i>
cdiamge ~# <i>cp -Rp /lib/modules/`uname -r` /mnt/gentoo/lib/modules</i>
</pre>

<p>
Make sure you <c>emerge hotplug</c> and have it added to the boot runlevel. To
have all modules that are currently running (from the LiveCD) loaded during
bootup of your Gentoo system, run the following command from within the chrooted
environment:
</p>

<pre caption="Adding all running modules to the modules.conf file">
# <i>cat /proc/modules | cut -d ' ' -f 1 &gt;&gt; \</i>
  <i>/etc/modules.autoload.d/kernel-`uname -r | cut -d . -f -2`</i>
# <i>modules-update</i>
</pre>

</body>
</section>
</chapter>

<chapter>
<title>Simplifying the Installation</title>
<section id="leave_terminal">
<title>Leaving your Terminal</title>
<body>

<p>
Many people want to leave their system when it's compiling. In certain cases
this is rather difficult as the installation is done in a public environment
where you cannot trust everyone. If this is the case, you want to be able to
perform the compilation in the background and log out from all terminals.
</p>

<p>
There are several possible solutions for this. The first one is to use
<c>screen</c>. After booting the LiveCD, set your root password and start a
screen session:
</p>

<note>
Not all LiveCDs provide screen. If this is the case, you will have to use one of
the other methods described in this section.
</note>

<pre caption="Starting a screen session">
# <i>screen -S gentoo</i>
</pre>

<p>
Once inside the screen session you can perform the entire installation. When you
want to leave your terminal, press <c>Ctrl-a, d</c> (that is, control and a at
the same time, then followed by a d) to <e>detach</e> your screen session. You
can now safely log out of your system.
</p>

<p>
To regain access to your terminal, log in as root again and <e>attach</e> to 
the running screen session:
</p>

<pre caption="Attaching to a screen session">
# <i>screen -x gentoo</i>
</pre>

<p>
If you can't use screen, there is still a way to leave your terminal. Follow the
installation instructions, but when you come to the point where a long-term
compilation would be started (for instance the <c>./scripts/bootstrap.sh</c>
step), use <c>nohup</c> which allows for a process to continue even when you log
out. Don't forget the trailing "&amp;", otherwise the process won't be placed in
the background! Remember where you are (the <c>pwd</c> command will show you
that) as you will need to know this later on.
</p>

<pre caption="Using nohup">
# <i>pwd</i>
/usr/portage
# <i>nohup ./scripts/bootstrap.sh &amp;</i>
</pre>

<p>
Now exit the chrooted environment (<c>exit</c>) and the LiveCD session. Your
compilation will continue in the background. 
</p>

<p>
When you want to check the compilation, log in as root (on the LiveCD) and
chroot back into your environment and go to the directory where you left off:
</p>

<pre caption="Chrooting back">
# <i>chroot /mnt/gentoo /bin/bash</i>
# <i>env-update &amp;&amp; source /etc/profile</i>
# <i>cd /usr/portage</i>
</pre>

<p>
Now use the <c>less</c> command on the <path>nohup.out</path> file that is
situated inside that directory. The compilation will append its output to that
file, so if you want to follow the compilation progress, run <c>less
nohup.out</c> and press <c>F</c> to follow the changes. When the compilation is
finished, you can continue with the next step of the installation instructions.
</p>

<p>
If you ever get tired of following the changes, press <c>Ctrl-C</c> followed by
a <c>q</c>. This won't stop the compilation process, only the <c>less</c>
process.
</p>

</body>
</section>
</chapter>

<chapter>
<title>Fixing Errors/Issues</title>
<section id="checking-disks">
<title>Extensive Testing of your Disks</title>
<body>

<p>
If you think your disk needs to be thoroughly checked for consistency (bad
sectors and such), you can use the <c>-c</c> option while placing the ext2 or
ext3 filesystem on it (using <c>mke2fs</c>). This will perform a read-test and 
will mark all bad blocks as such. If you are really paranoid, use <c>-c -c</c> 
to perform an extensive read/write test.
</p>

<pre caption="Checking for disk consistency">
# <i>mke2fs -j -c /dev/hda3</i>
</pre>

</body>
</section>
<section id="recover">
<title>Recovering from a malfunctioning installation</title>
<body>

<p>
If for some reason your Gentoo installation fails, you don't have to redo the
installation all over again. Instead, you can safely "go" to the point where you
think you made a mistake (or where you think the instructions are flawed) and
try a different approach.
</p>

<p>
First of all you need to chroot back into your Gentoo Linux environment. Follow
the instructions again, but ignore the partitioning steps as your partitions are
already created and even populated. You can therefore immediately mount those
partitions at <path>/mnt/gentoo</path>. You should also ignore the steps about
stage extraction and modifying <path>make.conf</path> - you don't want to 
overwrite your files do you?
</p>

<p>
Once chrooted inside your Gentoo Linux environment, immediately go to the step
where you think you should try a different approach. Don't redo all the steps
like bootstrapping and such unless that is the place where you think things
went wrong.
</p>

<p>
For instance, if you believe that you have a wrongly configured
<path>grub.conf</path>, you can immediately fire up your editor to update
<path>/boot/grub/grub.conf</path>.
</p>

<p>
Once you have tried a different approach for your situation, you should consider
how much of the subsequent steps you need to perform again. If the subsequent
steps are depending on your change, you will need to redo those. 
</p>

<p>
For instance,
</p>

<ul>
  <li>
    if you have changed a variable inside <path>make.conf</path> you will need 
    to do all subsequent compiling since those depend on the settings inside
    <path>make.conf</path>
  </li>
  <li>
    if you have altered <path>/boot/grub/grub.conf</path> you can immediately
    exit the chrooted environment and reboot as no subsequent steps are
    depending on <path>grub.conf</path>
  </li>
  <li>
    if you have recompiled your kernel you only need to make sure that your
    bootloader configuration points to the correct kernel image (double-check
    that you mounted your <path>/boot</path>!), then you can exit the chrooted
    environment and reboot
  </li>
  <li>
    if you have altered <path>/etc/fstab</path> you can exit the chrooted
    environment and reboot
  </li>
</ul>

<p>
As you can see, for most recovery operations you can immediately reboot. Only in
certain cases will you need to redo the subsequent installation steps.
</p>

</body>
</section>

</chapter>

</guide>
1	<?xml version='1.0' encoding="UTF-8"?>
2	<!DOCTYPE guide SYSTEM "/dtd/guide.dtd">
3	<!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/gentoo-x86-tipsntricks.xml,v 1.9 2004/09/22 21:57:14 neysx Exp $ -->
4
5	<guide link="/doc/en/gentoo-x86-tipsntricks.xml">
6	<title>Gentoo/x86 Installation Tips & Tricks</title>
7	<author title="Author">
8	<mail link="swift@gentoo.org">Sven Vermeulen</mail>
9	</author>
10
11	<abstract>
12	The Gentoo installation allows for very flexible approaches to the various
13	installation methods. As it is almost impossible to insert every single tip or
14	trick in the installation instructions this document tries to deal with all
15	submitted tips and tricks for reference purposes.
16	</abstract>
17
18	<license/>
19
20	<version>1.6</version>
21	<date>September 25, 2004</date>
22
23	<chapter>
24	<title>Introduction</title>
25	<section>
26	<title>Preliminary</title>
27	<body>
28
29	<p>
30	This document contains various tips and tricks for the Gentoo/x86 installation.
31	Most of them are discussed in a dense way - they are meant as an addendum to the
32	installation instructions and not as a replacement.
33	</p>
34
35	</body>
36	</section>
37	<section>
38	<title>Contents</title>
39	<body>
40
41	<p>
42	<b>Advanced Installations</b>
43	</p>
44
45	<ul>
46	<li><uri link="#software-raid">Software RAID</uri></li>
47	<li><uri link="#ata-raid-2.4">ATA RAID using 2.4 kernels</uri></li>
48	<li><uri link="#livecd-kernel">Using the LiveCD kernel</uri></li>
49	</ul>
50
51	<p>
52	<b>Simplifying the Installation</b>
53	</p>
54
55	<ul>
56	<li><uri link="#leave_terminal">Leaving the Terminal</uri></li>
57	</ul>
58
59	<p>
60	<b>Fixing Errors/Issues</b>
61	</p>
62
63	<ul>
64	<li><uri link="#checking-disks">Extensive Testing of your Disks</uri></li>
65	<li>
66	<uri link="#recover">Recovering from a malfunctioning installation</uri>
67	</li>
68	</ul>
69
70	</body>
71	</section>
72	</chapter>
73	<chapter>
74	<title>Advanced Installations</title>
75	<section id="software-raid">
76	<title>Software RAID</title>
77	<body>
78
79	<note>
80	If you are not known to software raid, please read the <uri
81	link="http://tldp.org/HOWTO/Software-RAID-HOWTO.html">Software-RAID-HOWTO</uri>.
82	</note>
83
84	<p>
85	Once you are booted from the LiveCD, load the appropriate RAID modules. For
86	instance, if you plan on using RAID-1:
87	</p>
88
89	<pre caption="Loading the RAID-1 module">
90	# <i>modprobe raid1</i>
91	</pre>
92
93	<p>
94	When you partition your disks, make sure that your partitions use <c>fd</c>
95	(Linux raid autodetect) as Partition Type instead of <c>83</c> (Linux native).
96	You can alter the partition type using the <c>t</c> command in <c>fdisk</c>.
97	</p>
98
99	<p>
100	After partitioning, create the <path>/etc/mdadm.conf</path> file (yes, indeed,
101	on the LiveCD environment) using <c>mdadm</c>, an advanced tool for <uri
102	link="http://www.linuxdevcenter.com/pub/a/linux/2002/12/05/RAID.html">RAID
103	management</uri>. For instance, to have your boot, swap and root partition
104	mirrored (RAID-1) covering <path>/dev/sda</path> and <path>/dev/sdb</path>,
105	you can use:
106	</p>
107
108	<pre caption="mdadm command example">
109	# <i>mdadm --create --verbose /dev/md0 --level=1 --raid-devices=2 /dev/sda1 /dev/sdb1</i>
110	# <i>mdadm --create --verbose /dev/md1 --level=1 --raid-devices=2 /dev/sda2 /dev/sdb2</i>
111	# <i>mdadm --create --verbose /dev/md2 --level=1 --raid-devices=2 /dev/sda3 /dev/sdb3</i>
112	</pre>
113
114	<p>
115	The Linux Software RAID driver will start creating the metadevices. You can see
116	its progress in <path>/proc/mdstat</path>. Wait until the metadevices are
117	completely finished before proceeding.
118	</p>
119
120	<p>
121	From now onwards, use <path>/dev/md0</path> for the boot partition,
122	<path>/dev/md1</path> for the swap partition and <path>/dev/md2</path> for the
123	root partition.
124	</p>
125
126	<p>
127	After mounting <path>/dev/md2</path> on <path>/mnt/gentoo</path>, don't forget
128	to copy over <path>/etc/mdadm.conf</path> to <path>/mnt/gentoo/etc</path>.
129	</p>
130
131	<p>
132	When you're configuring your kernel, make sure you have the appropriate RAID
133	support <e>in</e> your kernel and not as module.
134	</p>
135
136	<p>
137	When installing extra tools, emerge <c>mdadm</c> as well. Note that this
138	isn't available on all LiveCDs so you might not be able to install Gentoo on a
139	Software RAID when using a networkless installation!
140	</p>
141
142	<p>
143	When configuring your bootloader, make sure it gets installed in the MBR of
144	<e>both</e> disks if you use mirroring.
145	</p>
146
147	</body>
148	</section>
149	<section id="ata-raid-2.4">
150	<title>ATA RAID using 2.4 kernels</title>
151	<body>
152
153	<p>
154	Make sure you boot your LiveCD using the <c>doataraid</c> option. Once booted,
155	check the contents of <path>/dev/ataraid</path>. It should contain various
156	<path>disc*</path> directories for each harddisk available in the ATA RAID. An
157	entire disk is displayed as <path>disc</path> while partitions are
158	<path>part*</path>.
159	</p>
160
161	<p>
162	Write down the various <path>/dev/ataraid/disc/</path> device files that you
163	use to install Gentoo on. You will need to substitute the <path>/dev/hda</path>
164	examples in the installation with this path.
165	</p>
166
167	<p>
168	Before chrooting, bind-mount the <path>/dev</path> structure in the new
169	environment:
170	</p>
171
172	<pre caption="Bind-mounting /dev">
173	# <i>mount -o bind /dev /mnt/gentoo/dev</i>
174	</pre>
175
176	<p>
177	When configuring your kernel, make sure you enable support for your ATA RAID
178	chipset and options. For instance, a popular ATA RAID system is a <e>Promise
179	FastTrack built-in RAID</e> in which case you definitely need <c>Promise
180	FastTrack Options</c> built in into your kernel.
181	</p>
182
183	<p>
184	When configuring GRUB, you first have to create a GRUB bootdisk. This is not as
185	hard as you think. First install GRUB as you would, but when you come to the
186	part where GRUB is getting installed in the MBR, follow the following
187	instructions:
188	</p>
189
190	<pre caption="Creating a GRUB bootdisk">
191	# <i>cd /boot/grub</i>
192	# <i>dd if=stage1 of=/dev/fd0 bs=512 count=1</i>
193	# <i>dd if=stage2 of=/dev/fd0 bs=512 seek=1</i>
194	</pre>
195
196	<p>
197	You still need to write your <path>grub.conf</path> file. This is no different
198	from the installation instructions, just make sure that your <c>root=</c> points
199	to the ATA RAID device.
200	</p>
201
202	<p>
203	After finishing the installation, boot with your GRUB bootdisk. You will be
204	greeted by a GRUB prompt. Now configure GRUB to boot from the ATA RAID device:
205	</p>
206
207	<pre caption="Installing GRUB on the ATA RAID">
208	grub> root (hd0,x)
209	grub> setup (hd0)
210	grub> quit
211	</pre>
212
213	<p>
214	Now reboot (with the GRUB bootfloppy removed).
215	</p>
216
217	<p>
218	LILO users can safely use the instructions mentioned in the installation
219	instructions.
220	</p>
221
222	</body>
223	</section>
224	<section id="livecd-kernel">
225	<title>Using the LiveCD kernel</title>
226	<body>
227
228	<p>
229	If you don't want to compile a kernel yourself you can use the kernel from the
230	LiveCD and copy it to your system. When you come to the point that you're asked
231	to compile a kernel, go to another terminal (press Alt-F2) and log in with the
232	root password you've supplied at the beginning of the installation.
233	</p>
234
235	<p>
236	Copy over the kernel and modules to your Gentoo system:
237	</p>
238
239	<pre caption="Copying over the LiveCD kernel">
240	<comment>(${KN} is the kernel name, usually something like 'gentoo' or 'smp')</comment>
241	cdimage ~# <i>cp /mnt/cdrom/isolinux/${KN} /mnt/cdrom/isolinux/${KN}.gz /mnt/gentoo/boot</i>
242	cdimage ~# <i>mkdir -p /mnt/gentoo/lib/modules</i>
243	cdiamge ~# <i>cp -Rp /lib/modules/`uname -r` /mnt/gentoo/lib/modules</i>
244	</pre>
245
246	<p>
247	Make sure you <c>emerge hotplug</c> and have it added to the boot runlevel. To
248	have all modules that are currently running (from the LiveCD) loaded during
249	bootup of your Gentoo system, run the following command from within the chrooted
250	environment:
251	</p>
252
253	<pre caption="Adding all running modules to the modules.conf file">
254	# <i>cat /proc/modules \| cut -d ' ' -f 1 >> \</i>
255	<i>/etc/modules.autoload.d/kernel-`uname -r \| cut -d . -f -2`</i>
256	# <i>modules-update</i>
257	</pre>
258
259	</body>
260	</section>
261	</chapter>
262
263	<chapter>
264	<title>Simplifying the Installation</title>
265	<section id="leave_terminal">
266	<title>Leaving your Terminal</title>
267	<body>
268
269	<p>
270	Many people want to leave their system when it's compiling. In certain cases
271	this is rather difficult as the installation is done in a public environment
272	where you cannot trust everyone. If this is the case, you want to be able to
273	perform the compilation in the background and log out from all terminals.
274	</p>
275
276	<p>
277	There are several possible solutions for this. The first one is to use
278	<c>screen</c>. After booting the LiveCD, set your root password and start a
279	screen session:
280	</p>
281
282	<note>
283	Not all LiveCDs provide screen. If this is the case, you will have to use one of
284	the other methods described in this section.
285	</note>
286
287	<pre caption="Starting a screen session">
288	# <i>screen -S gentoo</i>
289	</pre>
290
291	<p>
292	Once inside the screen session you can perform the entire installation. When you
293	want to leave your terminal, press <c>Ctrl-a, d</c> (that is, control and a at
294	the same time, then followed by a d) to <e>detach</e> your screen session. You
295	can now safely log out of your system.
296	</p>
297
298	<p>
299	To regain access to your terminal, log in as root again and <e>attach</e> to
300	the running screen session:
301	</p>
302
303	<pre caption="Attaching to a screen session">
304	# <i>screen -x gentoo</i>
305	</pre>
306
307	<p>
308	If you can't use screen, there is still a way to leave your terminal. Follow the
309	installation instructions, but when you come to the point where a long-term
310	compilation would be started (for instance the <c>./scripts/bootstrap.sh</c>
311	step), use <c>nohup</c> which allows for a process to continue even when you log
312	out. Don't forget the trailing "&", otherwise the process won't be placed in
313	the background! Remember where you are (the <c>pwd</c> command will show you
314	that) as you will need to know this later on.
315	</p>
316
317	<pre caption="Using nohup">
318	# <i>pwd</i>
319	/usr/portage
320	# <i>nohup ./scripts/bootstrap.sh &</i>
321	</pre>
322
323	<p>
324	Now exit the chrooted environment (<c>exit</c>) and the LiveCD session. Your
325	compilation will continue in the background.
326	</p>
327
328	<p>
329	When you want to check the compilation, log in as root (on the LiveCD) and
330	chroot back into your environment and go to the directory where you left off:
331	</p>
332
333	<pre caption="Chrooting back">
334	# <i>chroot /mnt/gentoo /bin/bash</i>
335	# <i>env-update && source /etc/profile</i>
336	# <i>cd /usr/portage</i>
337	</pre>
338
339	<p>
340	Now use the <c>less</c> command on the <path>nohup.out</path> file that is
341	situated inside that directory. The compilation will append its output to that
342	file, so if you want to follow the compilation progress, run <c>less
343	nohup.out</c> and press <c>F</c> to follow the changes. When the compilation is
344	finished, you can continue with the next step of the installation instructions.
345	</p>
346
347	<p>
348	If you ever get tired of following the changes, press <c>Ctrl-C</c> followed by
349	a <c>q</c>. This won't stop the compilation process, only the <c>less</c>
350	process.
351	</p>
352
353	</body>
354	</section>
355	</chapter>
356
357	<chapter>
358	<title>Fixing Errors/Issues</title>
359	<section id="checking-disks">
360	<title>Extensive Testing of your Disks</title>
361	<body>
362
363	<p>
364	If you think your disk needs to be thoroughly checked for consistency (bad
365	sectors and such), you can use the <c>-c</c> option while placing the ext2 or
366	ext3 filesystem on it (using <c>mke2fs</c>). This will perform a read-test and
367	will mark all bad blocks as such. If you are really paranoid, use <c>-c -c</c>
368	to perform an extensive read/write test.
369	</p>
370
371	<pre caption="Checking for disk consistency">
372	# <i>mke2fs -j -c /dev/hda3</i>
373	</pre>
374
375	</body>
376	</section>
377	<section id="recover">
378	<title>Recovering from a malfunctioning installation</title>
379	<body>
380
381	<p>
382	If for some reason your Gentoo installation fails, you don't have to redo the
383	installation all over again. Instead, you can safely "go" to the point where you
384	think you made a mistake (or where you think the instructions are flawed) and
385	try a different approach.
386	</p>
387
388	<p>
389	First of all you need to chroot back into your Gentoo Linux environment. Follow
390	the instructions again, but ignore the partitioning steps as your partitions are
391	already created and even populated. You can therefore immediately mount those
392	partitions at <path>/mnt/gentoo</path>. You should also ignore the steps about
393	stage extraction and modifying <path>make.conf</path> - you don't want to
394	overwrite your files do you?
395	</p>
396
397	<p>
398	Once chrooted inside your Gentoo Linux environment, immediately go to the step
399	where you think you should try a different approach. Don't redo all the steps
400	like bootstrapping and such unless that is the place where you think things
401	went wrong.
402	</p>
403
404	<p>
405	For instance, if you believe that you have a wrongly configured
406	<path>grub.conf</path>, you can immediately fire up your editor to update
407	<path>/boot/grub/grub.conf</path>.
408	</p>
409
410	<p>
411	Once you have tried a different approach for your situation, you should consider
412	how much of the subsequent steps you need to perform again. If the subsequent
413	steps are depending on your change, you will need to redo those.
414	</p>
415
416	<p>
417	For instance,
418	</p>
419
420	<ul>
421	<li>
422	if you have changed a variable inside <path>make.conf</path> you will need
423	to do all subsequent compiling since those depend on the settings inside
424	<path>make.conf</path>
425	</li>
426	<li>
427	if you have altered <path>/boot/grub/grub.conf</path> you can immediately
428	exit the chrooted environment and reboot as no subsequent steps are
429	depending on <path>grub.conf</path>
430	</li>
431	<li>
432	if you have recompiled your kernel you only need to make sure that your
433	bootloader configuration points to the correct kernel image (double-check
434	that you mounted your <path>/boot</path>!), then you can exit the chrooted
435	environment and reboot
436	</li>
437	<li>
438	if you have altered <path>/etc/fstab</path> you can exit the chrooted
439	environment and reboot
440	</li>
441	</ul>
442
443	<p>
444	As you can see, for most recovery operations you can immediately reboot. Only in
445	certain cases will you need to redo the subsequent installation steps.
446	</p>
447
448	</body>
449	</section>
450
451	</chapter>
452
453	</guide>