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1 swift 1.1 <?xml version='1.0' encoding="UTF-8"?>
2     <!DOCTYPE guide SYSTEM "/dtd/guide.dtd">
3 swift 1.13 <!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/gentoo-x86-tipsntricks.xml,v 1.12 2005/05/12 09:40:22 neysx Exp $ -->
4 swift 1.1
5     <guide link="/doc/en/gentoo-x86-tipsntricks.xml">
6     <title>Gentoo/x86 Installation Tips &amp; 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 swift 1.13 <version>1.8</version>
21     <date>2005-07-02</date>
22 swift 1.1
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 swift 1.2 <p>
42     <b>Advanced Installations</b>
43     </p>
44    
45 swift 1.1 <ul>
46     <li><uri link="#software-raid">Software RAID</uri></li>
47 swift 1.4 <li><uri link="#ata-raid-2.4">ATA RAID using 2.4 kernels</uri></li>
48 swift 1.10 <li><uri link="#livecd-kernel">Using the LiveCD kernel</uri></li>
49 swift 1.1 </ul>
50    
51 swift 1.3 <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 swift 1.5 <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 swift 1.6 <li>
66     <uri link="#recover">Recovering from a malfunctioning installation</uri>
67     </li>
68 swift 1.5 </ul>
69    
70 swift 1.1 </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 neysx 1.12 If you are not familiar with software raid, please read the <uri
81 swift 1.1 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 swift 1.11 Now before we start creating the RAID arrays, we need to create the metadevice
101     nodes:
102     </p>
103    
104     <pre caption="Creating metadevice nodes">
105     # <i>mknod /dev/md0 b 9 0</i>
106     # <i>mknod /dev/md1 b 9 1</i>
107     # <i>mknod /dev/md2 b 9 2</i>
108     </pre>
109    
110     <p>
111 swift 1.8 After partitioning, create the <path>/etc/mdadm.conf</path> file (yes, indeed,
112     on the LiveCD environment) using <c>mdadm</c>, an advanced tool for <uri
113 swift 1.7 link="http://www.linuxdevcenter.com/pub/a/linux/2002/12/05/RAID.html">RAID
114     management</uri>. For instance, to have your boot, swap and root partition
115     mirrored (RAID-1) covering <path>/dev/sda</path> and <path>/dev/sdb</path>,
116     you can use:
117 swift 1.1 </p>
118    
119 swift 1.7 <pre caption="mdadm command example">
120     # <i>mdadm --create --verbose /dev/md0 --level=1 --raid-devices=2 /dev/sda1 /dev/sdb1</i>
121     # <i>mdadm --create --verbose /dev/md1 --level=1 --raid-devices=2 /dev/sda2 /dev/sdb2</i>
122     # <i>mdadm --create --verbose /dev/md2 --level=1 --raid-devices=2 /dev/sda3 /dev/sdb3</i>
123 swift 1.13 <comment>(Save information about the created devices in mdadm.conf)</comment>
124     # <i>mdadm --detail --scan > /etc/mdadm.conf</i>
125 swift 1.1 </pre>
126    
127     <p>
128     The Linux Software RAID driver will start creating the metadevices. You can see
129     its progress in <path>/proc/mdstat</path>. Wait until the metadevices are
130     completely finished before proceeding.
131     </p>
132    
133     <p>
134     From now onwards, use <path>/dev/md0</path> for the boot partition,
135     <path>/dev/md1</path> for the swap partition and <path>/dev/md2</path> for the
136     root partition.
137     </p>
138    
139     <p>
140     After mounting <path>/dev/md2</path> on <path>/mnt/gentoo</path>, don't forget
141 swift 1.8 to copy over <path>/etc/mdadm.conf</path> to <path>/mnt/gentoo/etc</path>.
142 swift 1.1 </p>
143    
144     <p>
145     When you're configuring your kernel, make sure you have the appropriate RAID
146     support <e>in</e> your kernel and not as module.
147     </p>
148    
149     <p>
150 swift 1.8 When installing extra tools, emerge <c>mdadm</c> as well. Note that this
151 swift 1.1 isn't available on all LiveCDs so you might not be able to install Gentoo on a
152     Software RAID when using a networkless installation!
153     </p>
154    
155     <p>
156     When configuring your bootloader, make sure it gets installed in the MBR of
157     <e>both</e> disks if you use mirroring.
158     </p>
159    
160     </body>
161     </section>
162 swift 1.4 <section id="ata-raid-2.4">
163     <title>ATA RAID using 2.4 kernels</title>
164     <body>
165    
166     <p>
167     Make sure you boot your LiveCD using the <c>doataraid</c> option. Once booted,
168     check the contents of <path>/dev/ataraid</path>. It should contain various
169     <path>disc*</path> directories for each harddisk available in the ATA RAID. An
170     entire disk is displayed as <path>disc</path> while partitions are
171     <path>part*</path>.
172     </p>
173    
174     <p>
175     Write down the various <path>/dev/ataraid/disc*/*</path> device files that you
176     use to install Gentoo on. You will need to substitute the <path>/dev/hda</path>
177     examples in the installation with this path.
178     </p>
179    
180     <p>
181     Before chrooting, bind-mount the <path>/dev</path> structure in the new
182     environment:
183     </p>
184    
185     <pre caption="Bind-mounting /dev">
186     # <i>mount -o bind /dev /mnt/gentoo/dev</i>
187     </pre>
188    
189     <p>
190     When configuring your kernel, make sure you enable support for your ATA RAID
191     chipset and options. For instance, a popular ATA RAID system is a <e>Promise
192     FastTrack built-in RAID</e> in which case you definitely need <c>Promise
193     FastTrack Options</c> built in into your kernel.
194     </p>
195    
196     <p>
197     When configuring GRUB, you first have to create a GRUB bootdisk. This is not as
198     hard as you think. First install GRUB as you would, but when you come to the
199     part where GRUB is getting installed in the MBR, follow the following
200     instructions:
201     </p>
202    
203     <pre caption="Creating a GRUB bootdisk">
204     # <i>cd /boot/grub</i>
205     # <i>dd if=stage1 of=/dev/fd0 bs=512 count=1</i>
206     # <i>dd if=stage2 of=/dev/fd0 bs=512 seek=1</i>
207     </pre>
208    
209     <p>
210     You still need to write your <path>grub.conf</path> file. This is no different
211     from the installation instructions, just make sure that your <c>root=</c> points
212     to the ATA RAID device.
213     </p>
214    
215     <p>
216     After finishing the installation, boot with your GRUB bootdisk. You will be
217     greeted by a GRUB prompt. Now configure GRUB to boot from the ATA RAID device:
218     </p>
219    
220     <pre caption="Installing GRUB on the ATA RAID">
221     grub&gt; root (hd0,x)
222     grub&gt; setup (hd0)
223     grub&gt; quit
224     </pre>
225    
226     <p>
227     Now reboot (with the GRUB bootfloppy removed).
228     </p>
229    
230     <p>
231     LILO users can safely use the instructions mentioned in the installation
232     instructions.
233     </p>
234    
235     </body>
236     </section>
237 swift 1.10 <section id="livecd-kernel">
238     <title>Using the LiveCD kernel</title>
239     <body>
240    
241     <p>
242     If you don't want to compile a kernel yourself you can use the kernel from the
243     LiveCD and copy it to your system. When you come to the point that you're asked
244     to compile a kernel, go to another terminal (press Alt-F2) and log in with the
245     root password you've supplied at the beginning of the installation.
246     </p>
247    
248     <p>
249     Copy over the kernel and modules to your Gentoo system:
250     </p>
251    
252     <pre caption="Copying over the LiveCD kernel">
253     <comment>(${KN} is the kernel name, usually something like 'gentoo' or 'smp')</comment>
254     cdimage ~# <i>cp /mnt/cdrom/isolinux/${KN} /mnt/cdrom/isolinux/${KN}.gz /mnt/gentoo/boot</i>
255     cdimage ~# <i>mkdir -p /mnt/gentoo/lib/modules</i>
256     cdiamge ~# <i>cp -Rp /lib/modules/`uname -r` /mnt/gentoo/lib/modules</i>
257     </pre>
258    
259     <p>
260     Make sure you <c>emerge hotplug</c> and have it added to the boot runlevel. To
261     have all modules that are currently running (from the LiveCD) loaded during
262     bootup of your Gentoo system, run the following command from within the chrooted
263     environment:
264     </p>
265    
266     <pre caption="Adding all running modules to the modules.conf file">
267     # <i>cat /proc/modules | cut -d ' ' -f 1 &gt;&gt; \</i>
268     <i>/etc/modules.autoload.d/kernel-`uname -r | cut -d . -f -2`</i>
269     # <i>modules-update</i>
270     </pre>
271    
272     </body>
273     </section>
274 swift 1.1 </chapter>
275 swift 1.3
276     <chapter>
277     <title>Simplifying the Installation</title>
278     <section id="leave_terminal">
279     <title>Leaving your Terminal</title>
280     <body>
281    
282     <p>
283     Many people want to leave their system when it's compiling. In certain cases
284     this is rather difficult as the installation is done in a public environment
285     where you cannot trust everyone. If this is the case, you want to be able to
286     perform the compilation in the background and log out from all terminals.
287     </p>
288    
289     <p>
290     There are several possible solutions for this. The first one is to use
291     <c>screen</c>. After booting the LiveCD, set your root password and start a
292     screen session:
293     </p>
294    
295     <note>
296     Not all LiveCDs provide screen. If this is the case, you will have to use one of
297     the other methods described in this section.
298     </note>
299    
300     <pre caption="Starting a screen session">
301     # <i>screen -S gentoo</i>
302     </pre>
303    
304     <p>
305     Once inside the screen session you can perform the entire installation. When you
306     want to leave your terminal, press <c>Ctrl-a, d</c> (that is, control and a at
307     the same time, then followed by a d) to <e>detach</e> your screen session. You
308     can now safely log out of your system.
309     </p>
310    
311     <p>
312     To regain access to your terminal, log in as root again and <e>attach</e> to
313     the running screen session:
314     </p>
315    
316     <pre caption="Attaching to a screen session">
317     # <i>screen -x gentoo</i>
318     </pre>
319    
320     <p>
321     If you can't use screen, there is still a way to leave your terminal. Follow the
322     installation instructions, but when you come to the point where a long-term
323     compilation would be started (for instance the <c>./scripts/bootstrap.sh</c>
324     step), use <c>nohup</c> which allows for a process to continue even when you log
325     out. Don't forget the trailing "&amp;", otherwise the process won't be placed in
326     the background! Remember where you are (the <c>pwd</c> command will show you
327     that) as you will need to know this later on.
328     </p>
329    
330     <pre caption="Using nohup">
331     # <i>pwd</i>
332     /usr/portage
333     # <i>nohup ./scripts/bootstrap.sh &amp;</i>
334     </pre>
335    
336     <p>
337     Now exit the chrooted environment (<c>exit</c>) and the LiveCD session. Your
338     compilation will continue in the background.
339     </p>
340    
341     <p>
342     When you want to check the compilation, log in as root (on the LiveCD) and
343     chroot back into your environment and go to the directory where you left off:
344     </p>
345    
346     <pre caption="Chrooting back">
347     # <i>chroot /mnt/gentoo /bin/bash</i>
348     # <i>env-update &amp;&amp; source /etc/profile</i>
349     # <i>cd /usr/portage</i>
350     </pre>
351    
352     <p>
353     Now use the <c>less</c> command on the <path>nohup.out</path> file that is
354     situated inside that directory. The compilation will append its output to that
355     file, so if you want to follow the compilation progress, run <c>less
356     nohup.out</c> and press <c>F</c> to follow the changes. When the compilation is
357     finished, you can continue with the next step of the installation instructions.
358     </p>
359    
360     <p>
361     If you ever get tired of following the changes, press <c>Ctrl-C</c> followed by
362     a <c>q</c>. This won't stop the compilation process, only the <c>less</c>
363     process.
364     </p>
365    
366     </body>
367     </section>
368     </chapter>
369    
370 swift 1.5 <chapter>
371     <title>Fixing Errors/Issues</title>
372     <section id="checking-disks">
373     <title>Extensive Testing of your Disks</title>
374     <body>
375    
376     <p>
377     If you think your disk needs to be thoroughly checked for consistency (bad
378     sectors and such), you can use the <c>-c</c> option while placing the ext2 or
379     ext3 filesystem on it (using <c>mke2fs</c>). This will perform a read-test and
380     will mark all bad blocks as such. If you are really paranoid, use <c>-c -c</c>
381     to perform an extensive read/write test.
382     </p>
383    
384     <pre caption="Checking for disk consistency">
385     # <i>mke2fs -j -c /dev/hda3</i>
386     </pre>
387    
388     </body>
389     </section>
390 swift 1.6 <section id="recover">
391     <title>Recovering from a malfunctioning installation</title>
392     <body>
393    
394     <p>
395     If for some reason your Gentoo installation fails, you don't have to redo the
396     installation all over again. Instead, you can safely "go" to the point where you
397     think you made a mistake (or where you think the instructions are flawed) and
398     try a different approach.
399     </p>
400    
401     <p>
402     First of all you need to chroot back into your Gentoo Linux environment. Follow
403     the instructions again, but ignore the partitioning steps as your partitions are
404     already created and even populated. You can therefore immediately mount those
405     partitions at <path>/mnt/gentoo</path>. You should also ignore the steps about
406     stage extraction and modifying <path>make.conf</path> - you don't want to
407     overwrite your files do you?
408     </p>
409    
410     <p>
411     Once chrooted inside your Gentoo Linux environment, immediately go to the step
412     where you think you should try a different approach. Don't redo all the steps
413     like bootstrapping and such unless that is the place where you think things
414     went wrong.
415     </p>
416    
417     <p>
418     For instance, if you believe that you have a wrongly configured
419     <path>grub.conf</path>, you can immediately fire up your editor to update
420     <path>/boot/grub/grub.conf</path>.
421     </p>
422    
423     <p>
424     Once you have tried a different approach for your situation, you should consider
425     how much of the subsequent steps you need to perform again. If the subsequent
426     steps are depending on your change, you will need to redo those.
427     </p>
428    
429     <p>
430     For instance,
431     </p>
432    
433     <ul>
434     <li>
435     if you have changed a variable inside <path>make.conf</path> you will need
436     to do all subsequent compiling since those depend on the settings inside
437     <path>make.conf</path>
438     </li>
439     <li>
440     if you have altered <path>/boot/grub/grub.conf</path> you can immediately
441     exit the chrooted environment and reboot as no subsequent steps are
442     depending on <path>grub.conf</path>
443     </li>
444     <li>
445     if you have recompiled your kernel you only need to make sure that your
446     bootloader configuration points to the correct kernel image (double-check
447     that you mounted your <path>/boot</path>!), then you can exit the chrooted
448     environment and reboot
449     </li>
450     <li>
451     if you have altered <path>/etc/fstab</path> you can exit the chrooted
452     environment and reboot
453     </li>
454     </ul>
455    
456     <p>
457     As you can see, for most recovery operations you can immediately reboot. Only in
458     certain cases will you need to redo the subsequent installation steps.
459     </p>
460    
461     </body>
462     </section>
463    
464 swift 1.5 </chapter>
465    
466 swift 1.1 </guide>

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