In this section we will describe each installer component in
detail. The components have been grouped into stages that should
be recognizable for users. They are presented in the order they
appear during the install. Note that not all modules will be used
for every installation; which modules are actually used depends on
the installation method you use and on your hardware.
6.3.1. Setting up Debian Installer and Hardware Configuration
Let's assume the Debian Installer has booted and you are facing its
first screen. At this time, the capabilities of debian-installer are still quite
limited. It doesn't know much about your hardware, preferred language,
or even the task it should perform. Don't worry. Because debian-installer is quite
clever, it can automatically probe your hardware, locate the rest
of its components and upgrade itself to a capable installation system.
However, you still need to help debian-installer with some information it can't
determine automatically (like selecting your preferred language, keyboard
layout or desired network mirror).
You will notice that debian-installer performs hardware detection
several times during this stage. The first time is targeted specifically
at the hardware needed to load installer components (e.g. your CD-ROM or
network card). As not all drivers may be available during this first run,
hardware detection needs to be repeated later in the process.
188.8.131.52. Check available memory
One of the first things debian-installer does, is to check available memory.
If the available memory is limited, this component will make some
changes in the installation process which hopefully will allow
you to install Debian GNU/Linux on your system.
During a low memory install, not all components will be available.
One of the limitations is that you won't be able to choose a
language for the installation.
184.108.40.206. Language selection
As the first step of the installation, select the language in which
you want the installation process to proceed. The language names
are listed in both English (left side) and in the language itself
(right side); the names on the right side are also shown in the proper
script for the language. The list is sorted on the English names.
The language you choose will be used for the rest of the installation
process, provided a translation of the different dialogs is available.
If no valid translation is available for the selected language, the
installer will default to English. The selected language will also be
used to help select a suitable keyboard layout.
220.127.116.11. Country selection
If you selected a language in Section 18.104.22.168, “Language selection” which has
more than one country associated with it (true for Chinese, English,
French, and many other languages), you can specify the country here.
If you choose Other at the bottom of the list,
you will be presented with a list of all countries, grouped by continent.
This selection will be used later in the installation process to pick the
default timezone and a Debian mirror appropriate for your geographic
location. If the defaults proposed by the installer are not suitable, you
can make a different choice. The selected country, together with the selected
language, may also affect locale settings for your new Debian system.
22.214.171.124. Choosing a Keyboard
Keyboards are often tailored to the characters used in a language.
Select a layout that conforms to the keyboard you are using, or
select something close if the keyboard layout you want
isn't represented. Once the system installation is complete, you'll be
able to select a keyboard layout from a wider range of choices (run
kbdconfig as root after you have completed the
Move the highlight to the keyboard selection you desire and press
Enter. Use the arrow keys to move the highlight — they are
in the same place in all national language keyboard layouts, so they
are independent of the keyboard configuration. An 'extended' keyboard
is one with F1 through F10 keys
along the top row.
126.96.36.199. Looking for the Debian Installer ISO Image
When installing via the hd-media method, there
will be a moment where you need to find and mount the Debian Installer
iso image in order to get the rest of the installation files. The
component iso-scan does exactly this.
At first, iso-scan automatically mounts all block
devices (e.g. partitions) which have some known filesystem on them and
sequentially searches for filenames ending with
.iso (or .ISO for that
matter). Beware that the first attempt scans only files in the root
directory and in the first level of subdirectories (i.e. it finds
After an iso image has been found, iso-scan checks
its content to determine if the image is a valid Debian iso image or
not. In the former case we are done, in the latter
iso-scan seeks for another image.
In case the previous attempt to find an installer iso image fails,
iso-scan will ask you whether you would like to
perform a more thorough search. This pass doesn't just look into the
topmost directories, but really traverses whole filesystem.
If iso-scan does not discover your installer iso
image, reboot back to your original operating system and check if the
image is named correctly (ending in .iso), if it is
placed on a filesystem recognizable by debian-installer, and if it is not
corrupted (verify the checksum). Experienced Unix users could do this
without rebooting on the second console.
188.8.131.52. Configuring Network
As you enter this step, if the system detects that you have more than
one network device, you'll be asked to choose which device will be
your primary network interface, i.e. the one
which you want to use for installation. The other interfaces won't be
configured at this time. You may configure additional interfaces after
installation is complete; see the interfaces(5) man page.
By default, debian-installer tries to configure your computer's network
automatically via DHCP. If the DHCP probe succeeds, you are done. If the
probe fails, it may be caused by many factors ranging from unplugged
network cable, to a misconfigured DHCP setup. Or maybe you don't have
a DHCP server in your local network at all. For further explanation
check the error messages on the third console. In any case, you will
be asked if you want to retry, or if you want to perform manual
setup. DHCP servers are sometimes really slow in their responses, so
if you are sure everything is in place, try again.
The manual network setup in turn asks you a number of questions about
your network, notably
Name server addresses, and a
Moreover, if you have a wireless network interface, you will be asked
to provide your Wireless ESSID and
a WEP key. Fill in the answers from
Section 3.3, “Information You Will Need”.
Some technical details you might, or might not, find handy: the
program assumes the network IP address is the bitwise-AND of your
system's IP address and your netmask. It will guess the broadcast
address is the bitwise OR of your system's IP address with the bitwise
negation of the netmask. It will also guess your gateway. If you
can't find any of these answers, use the system's guesses — you
can change them once the system has been installed, if necessary, by
editing /etc/network/interfaces. Alternatively,
you can install etherconf, which will step you
through your network setup.
6.3.2. Partitioning and Mount Point Selection
At this time, after hardware detection has been executed a final time,
debian-installer should be at its full strength, customized for the user's needs
and ready to do some real work.
As the title of this section indicates, the main task of the next few
components lies in partitioning your disks, creating filesystems,
assigning mountpoints and optionally configuring closely related issues
like LVM or RAID devices.
First you will be given the opportunity to automatically partition
either an entire drive, or free space on a drive. This is also called
“guided” partitioning. If you do not want to
autopartition, choose Manually edit partition
table from the menu.
If you choose guided partitioning, you will be able to choose from the
schemes listed in the table below. All schemes have their pros and cons,
some of which are discussed in Appendix B, Partitioning for Debian. If you are
unsure, choose the first one. Bear in mind, that guided partitioning
needs certain minimal amount of free space to operate with. If you don't
give it at least about 1GB of space (depends on chosen scheme), guided
partitioning will fail.
All files in one partition
/, /home, swap
After selecting a scheme, the next screen will show your new partition
table, including information on whether and how partitions will be
formatted and where they will be mounted.
This example shows two IDE harddrives divided into several partitions;
the first disk has some free space. Each partition line consists of the
partition number, its type, size, optional flags, file system, and
mountpoint (if any).
This concludes the guided partitioning. If you are satisfied with the
generated partition table, you can choose Finish
partitioning and write changes to disk from the menu to
implement the new partition table (as described at the end of this
section). If you are not happy, you can choose to Undo
changes to partitions, to run guided partitioning again
or modify the proposed changes as described below for manual partitioning.
A similar screen to the one shown just above will be displayed if you
choose manual partitioning except that your existing partition table will
be shown and without the mount points. How to manually setup your partition
table and the usage of partitions by your new Debian system will be covered
in the remainder of this section.
If you select a pristine disk which doesn't have neither partitions
nor free space on it, you will be offered to create a new partition
table (this is needed so you can create new partitions). After this
a new line entitled “FREE SPACE” should appear under the
If you select some free space, you will be offered to create new
partition. You will have to answer a quick series of questions about
its size, type (primary or logical), and location (beginning or end of
the free space). After this, you will be presented with detailed
overview of your new partition. There are options like mountpoint,
mount options, bootable flag, or way of usage. If you don't like the
preselected defaults, feel free to change them to your liking. E.g. by
selecting the option Use as:, you can
choose different filesystem for this partition including the
possibility to use the partition for swap, software RAID, LVM, or not
use it at all. Other nice feature is the possibility to copy data from
existing partition onto this one.
When you are satisfied with your new partition, select
Done setting up the partition and you will be
thrown back to the partman's main screen.
If you decide you want to change something about your partition,
simply select the partition, which will bring you to the partition
configuration menu. Because this is the same screen like when creating
a new partition, you can change the same set of options. One thing
which might not be very obvious at a first glance is that you can
resize the partition by selecting the item displaying the size of the
partition. Filesystems known to work are at least fat16, fat32, ext2,
ext3 and swap. This menu also allows you to delete a partition.
Be sure to create at least two partitions: one for the
root filesystem (which must be mounted as
/) and one for swap. If you
forget to mount the root filesystem, partman won't
let you continue until you correct this issue.
Capabilities of partman can be extended with installer
modules, but are dependent on your system's architecture. So if you can't
see all promised goodies, check if you have loaded all required modules
(e.g. partman-ext3, partman-xfs,
After you are satisfied with partitioning, select Finish
partitioning and write changes to disk from the partitioning
menu. You will be presented with a summary of changes made to the disks
and asked to confirm that the filesystems should be created as requested.
184.108.40.206. Configuring Logical Volume Manager (LVM)
If you are working with computers at the level of system administrator
or “advanced” user, you have surely seen the situation
where some disk partition (usually the most important one) was short on
space, while some other partition was grossly underused and you had to
manage this situation with moving stuff around, symlinking, etc.
To avoid the described situation you can use Logical Volume Manager
(LVM). Simply said, with LVM you can combine your partitions
(physical volumes in LVM lingo) to form
a virtual disc (so called volume group), which
can then be divided into virtual partitions (logical
volumes). The point is that logical volumes (and of course
underlying volume groups) can span across several physical discs.
Now when you realize you need more space for your old 160GB
/home partition, you can simply add a new 300GB
disc to the computer, join it with your existing volume group and then
resize the logical volume which holds your /home
filesystem and voila — your users have some room again on their
renewed 460GB partition. This example is of course a bit
oversimplified. If you haven't read it yet, you should consult the
LVM setup in debian-installer is quite simple. At first, you have to mark your
partitions to be used as physical volumes for LVM. (This is done in
partman in the Partition
settings menu where you should select Use as:->physical volume for
LVM.) Then start the
lvmcfg module (either directly from
partman or from the debian-installer's main menu) and combine
physical volumes to volume group(s) under the Modify
volume groups (VG) menu. After that, you should create
logical volumes on the top of volume groups from the menu
Modify logical volumes (LV).
After returning from lvmcfg back to
partman, you will see any created logical volumes
in the same way as ordinary partitions (and you should treat them like
If you have more than one harddrive in your computer, you can use
mdcfg to setup your drives for increased
performance and/or better reliability of your data. The result is
called Multidisk Device (or after its most
famous variant software RAID).
MD is basically a bunch of partitions located on different disks and
combined together to form a logical device. This
device can then be used like an ordinary partition (i.e. in
partman you can format it, assign a mountpoint,
The benefit you gain depends on a type of a MD device you are
creating. Currently supported are:
Is mainly aimed at performance. RAID0 splits all incoming data into
stripes and distributes them equally over each
disk in the array. This can increase the speed of read/write
operations, but when one of the disks fails, you will loose
everything (part of the information is still on
the healthy disk(s), the other part was on the
The typical use for RAID0 is a partition for video editing.
Is suitable for setups where reliability is the first concern. It
consists of several (usually two) equally sized partitions where every
partition contains exactly the same data. This essentially means three
things. First, if one of your disks fails, you still have the data
mirrored on the remaining disks. Second, you can use only a fraction
of the available capacity (more precisely, it is the size of the
smallest partition in the RAID). Third, file reads are load balanced among
the disks, which can improve performance on a server, such as a file
server, that tends to be loaded with more disk reads than writes.
Optionally you can have a spare disk in the array which will take the
place of the failed disk in the case of failure.
Is a good compromise between speed, reliability and data redundancy.
RAID5 splits all incomming data into stripes and distributes them
equally on all but one disks (similar to RAID0). Unlike RAID0, RAID5
also computes parity information, which gets
written on the remaining disk. The parity disk is not static (that
would be called RAID4), but is changing periodically, so the parity
information is distributed equally on all disks. When one of the
disks fails, the missing part of information can be computed from
remaining data and its parity. RAID5 must consist of at least three
active partitions. Optionally you can have a spare disk in the array
which will take the place of the failed disk in the case of failure.
As you can see, RAID5 has similar degree of reliability like RAID1
while achieving less redundancy. On the other hand it might be a bit
slower on write operation than RAID0 due to computation of parity
To sum it up:
Survives disk failure?
Size of the smallest partition multiplied by number of devices in RAID
Size of the smallest partition in RAID
Size of the smallest partition multiplied by (number of devices in
RAID minus one)
To create a MD device, you need to have the desired partitions it
should consist of marked for use in a RAID. (This is done in
partman in the Partition
settings menu where you should select Use as:->physical volume for
Support for MD is a relatively new addition to the installer.
You may experience problems for some RAID levels and in combination
with some bootloaders if you try to use MD for the root
(/) filesystem. For experienced users, it may be
possible to work around some of these problems by executing some
configuration or installation steps manually from a shell.
Next, you should choose Configure software
RAID from the main partman menu.
On the first screen of mdcfg simply select
Create MD device. You will be presented with
a list of supported types of MD devices, from which you should choose
one (e.g. RAID1). What follows depends on the type of MD you selected.
RAID0 is simple — you will be issued with the list of available
RAID partitions and your only task is to select the partitions which
will form the MD.
RAID1 is a bit more tricky. First, you will be asked to enter the
number of active devices and the number of spare devices which will
form the MD. Next, you need to select from the list of available RAID
partitions those that will be active and then those that will be
spare. The count of selected partitions must be equal to the number
provided few seconds ago. Don't worry. If you make a mistake and
select different number of partitions, the debian-installer won't let you
continue until you correct the issue.
RAID5 has similar setup procedure as RAID1 with the exception that you
need to use at least three active partitions.
It is perfectly possible to have several types of MD at once. For
example if you have three 200 GB hard drives dedicated to MD, each
containing two 100 GB partitions, you can combine first partitions on
all three disk into the RAID0 (fast 300 GB video editing partition)
and use the other three partitions (2 active and 1 spare) for RAID1
(quite reliable 100 GB partition for /home).
After you setup MD devices to your liking, you can
Finishmdcfg to return
back to the partman to create filesystems on your
new MD devices and assign them the usual attributes like mountpoints.
6.3.3. Installing the Base System
Although this stage is the least problematic, it consumes most time of
the install because it downloads, verifies and unpacks the whole base
system. If you have a slow computer or network connection, this could
take some time.
220.127.116.11. Base System Installation
During the Base installation, package unpacking and setup messages are
redirected to tty3. You can access this
terminal by pressing
get back to the main installer process with
The unpack/setup messages generated by the base installation are saved in
/var/log/messages when the installation is
performed over a serial console.
As part of the installation, a Linux kernel will be installed. At the default
priority, the installer will choose one for you that best matches your
hardware. In lower priority modes, you will be able to choose from a list
of available kernels.
6.3.4. Making Your System Bootable
If you are installing a diskless workstation, obviously, booting off
the local disk isn't a meaningful option, and this step will be
Note that multiple operating systems booting on a single machine is
still something of a black art. This document does not even attempt
to document the various boot managers, which vary by architecture and
even by subarchitecture. You should see your boot manager's
documentation for more information.
18.104.22.168. Detecting other operating systems
Before a boot loader is installed, the installer will attempt to probe for
other operating systems which are installed on the machine. If it finds a
supported operating system, you will be informed of this during the boot
loader installation step, and the computer will be configured to boot this
other operating system in addition to Debian.
Note that multiple operating systems booting on a single machine is still
something of a black art. The automatic support for detecting and setting
up boot loaders to boot other operating systems varies by architecture and
even by subarchitecture. If it does not work you should consult your
boot manager's documentation for more information.
The installer may fail to detect other operating systems if the partitions on
which they reside are mounted when the detection takes place. This may occur if
you select a mountpoint (e.g. /win) for a partition containing another operating
system in partman, or if you have mounted partitions manually
from a console.
22.214.171.124. Install the Grub Boot Loader
on a Hard Disk
The main i386 boot loader is called “grub”.
Grub is a flexible and robust boot loader and a good default choice for
newbies and old hands alike.
By default, grub will be installed into the Master Boot Record (MBR), where
it will take over complete control of the boot process. If you prefer, you
can install it elsewhere. See the grub manual for complete information.
If you do not want to install grub at all, use the Back button to get to
the main menu, and from there select whatever bootloader you would like to
126.96.36.199. Install the LILO Boot Loader
on a Hard Disk
The second i386 boot loader is called “LILO”.
It is an old complex program which offers lots of functionality,
including DOS, Windows, and OS/2 boot management. Please carefully
read the instructions in the directory
/usr/share/doc/lilo/ if you have special needs;
also see the LILO mini-HOWTO.
Currently the LILO installation will only create menu entries for other
operating systems if these can be chainloaded.
This means you may have to manually add a menu entry for operating
systems like GNU/Linux and GNU/Hurd after the installation.
debian-installer presents you three choices where to install the
LILO boot loader:
Master Boot Record (MBR)
This way the LILO will take complete control of the
new Debian partition
Choose this if you want to use another boot
manager. LILO will install itself at the beginning
of the new Debian partition and it will serve as a secondary boot
Useful for advanced users who want to install LILO
somewhere else. In this case you will be asked for desired
location. You can use devfs style names, such as those that start with
/dev/ide, /dev/scsi, and
/dev/discs, as well as traditional names, such as
/dev/hda or /dev/sda.
If you can no longer boot into Windows 9x (or DOS) after this step,
you'll need to use a Windows 9x (MS-DOS) boot disk and use the
fdisk /mbr command to reinstall the MS-DOS
master boot record — however, this means that you'll need to use
some other way to get back into Debian! For more information on this
please read Section 8.3, “Reactivating DOS and Windows”.
188.8.131.52. Continue Without Boot Loader
This option can be used to complete the installation even when no boot
loader is to be installed, either because the arch/subarch doesn't
provide one, or because none is desired (e.g. you will use existing
If you plan to manually configure your bootloader, you should check the
name of the installed kernel in /target/boot.
You should also check that directory for the presence of an
initrd; if one is present, you will probably have
to instruct your bootloader to use it. Other information you will need
are the disk and partition you selected for your /
filesystem and, if you chose to install /boot on a
separate partition, also your /boot filesystem.
6.3.5. Finishing the First Stage
These are the last bits to do before rebooting to your new Debian. It
mostly consists of tidying up after the debian-installer.
184.108.40.206. Finish the Installation and Reboot
This is the last step in the initial Debian installation process. You will
be prompted to remove the boot media (CD, floppy, etc) that you used to
boot the installer. The installer will do any last minute tasks, and then
reboot into your new Debian system.
The components listed in this section are usually not involved in the
installation process, but are waiting in the background to help the
user in case something goes wrong.
220.127.116.11. Saving the installation logs
If the installation is successful, the logfiles created during
the installation process will be automatically saved to
/var/log/debian-installer/ on your new
Choosing Save debug logs from the main
menu allows you to save the log files to a floppy
disk. This can be useful if you encounter fatal problems
during the installation and wish to study the logs on another system
or attach them to an installation report.
18.104.22.168. Using the Shell and Viewing the Logs
There is an Execute a Shell item on the
menu. If the menu is not available when you need to use the shell,
press Left Alt-F2
(on a Mac keyboard, Option-F2) to switch to the second virtual
console. That's the Alt key on the
left-hand side of the space bar, and the
F2 function key, at the same time. This is a separate
window running a Bourne shell clone called ash.
At this point you are booted from the RAM disk, and there is a limited
set of Unix utilities available for your use. You can see what
programs are available with the command ls /bin /sbin /usr/bin
/usr/sbin and by typing help. The
text editor is nano. The shell has some nice features
like autocompletion and history.
Use the menus to perform any task that they are able to do — the
shell and commands are only there in case something goes wrong. In
particular, you should always use the menus, not the shell, to
activate your swap partition, because the menu software can't detect
that you've done this from the shell. Press Left
Alt-F1 to get back to menus, or
type exit if you used a menu item to open the
22.214.171.124. Installation Over the Network
One of the more interesting components is
network-console. It allows you to do a large
part of the installation over the network via SSH. The use of the
network implies you will have to perform the first steps of the
installation from the console, at least to the point of setting up
the networking. (Although you can automate that part with
Section 4.7, “Automatic Installation”.)
This component is not loaded into the main installation menu by default,
so you have to explicitly ask for it.
If you are installing from CD, you need to boot with medium priority or
otherwise invoke the main installation menu and choose Load
installer components from CD and from the list of
additional components select network-console: Continue
installation remotely using SSH. Successful load is
indicated by a new menu entry called Continue
installation remotely using SSH.
After selecting this new entry, you
will be asked for a new password
to be used for connecting to the installation system and for its
confirmation. That's all. Now you should see a screen which instructs
you to login remotely as the user installer with
the password you just provided. Another important detail to notice on
this screen is the fingerprint of this system. You need to transfer
the fingerprint securely to the “person who will continue the
Should you decide to continue with the installation locally, you
can always press Enter, which will bring you back to
the main menu, where you can select another component.
Now let's switch to the other side of the wire. As a prerequisite, you
need to configure your terminal for UTF-8 encoding, because that is
what the installation system uses. If you do not, remote installation
will be still possible, but you may encounter strange display
artefacts like destroyed dialog borders or unreadable non-ascii
characters. Establishing a connection with the installation system
is as simple as typing:
$ssh -l installer install_host
Where install_host is either the name
or IP address of the computer being installed. Before the actual
login the fingerprint of the remote system will be displayed and
you will have to confirm that it is correct.
If you install several computers in turn and they happen to have the
same IP address or hostname, ssh will refuse to connect
to such host. The reason is that it will have different fingerprint, which
is usually a sign of a spoofing attack. If you are sure this is not the
case, you will need to delete the relevant line from
~/.ssh/known_hosts and try again.
After the login you will be presented with an initial screen where you
have two possibilities called Start menu and
Start shell. The former brings you to the
main installer menu, where you can continue with the installation as
usual. The latter starts a shell from which you can examine and possibly
fix the remote system. You should only start one SSH session for the
installation menu, but may start multiple sessions for shells.
After you have started the installation remotely over SSH, you should
not go back to the installation session running on the local console.
Doing so may corrupt the database that holds the configuration of
the new system. This in turn may result in a failed installation or
problems with the installed system.
Also, if you are running the SSH session from an X terminal, you should
not resize the window as that will result in the connection being
126.96.36.199. Running base-config From Within debian-installer
It is possible to configure the base system within the first stage
installer (before rebooting from the hard drive), by running
base-config in a chroot
environment. This is mainly useful for testing the installer and
should normally be avoided.
To be honest, you can construct MD device even from partitions
residing on single physical drive, but that won't bring you anything