Hard Disk Upgrade Mini How-To

Hard Disk Upgrade Mini How-To
=============================

How to copy a Linux system from one hard disk to another

By Yves Bellefeuille <[email protected]>,
and Konrad Hinsen <[email protected]>
v2.1, 20 October 1999

This document explains how to transfer, or migrate, an entire Linux
system, including LILO, from one hard disk to another.

In the following explanation, "/dev/hda" (first IDE hard disk) means the
"old" disk, and "/dev/hdb" (second IDE hard disk) means the "new" disk.

Specific partitions on the "old" disk are referred to as "/dev/hda1",
"/dev/hda2", and so on. Specific partitions on the "new" disk are
referred to as "/dev/hdb1", "/dev/hdb2", and so on.

The explanations in this document are based on Red Hat 6.0. They have
also been tested with Debian 2.1, Slackware 3.5 and SuSE 6.2; we
indicate a few differences to note if you're using those distributions.

If the commands don't work properly on your system, please let us know,
mentioning what distribution you're using.

1. Install both disks on your system
====================================

Modern systems can accept four "EIDE" devices on the hard disk
controller, so there shouldn't be any problem installing both disks on
your system at the same time, even if you also have other EIDE devices.
Hard disks and CD-ROM drives are typical EIDE devices. Floppy drives and
tape drives are usually connected to the floppy drive controller rather
than to the hard disk controller.

SCSI adapters are even more flexible and can accept seven devices. If
you're lucky (and rich) enough to have a SCSI adapter, you probably
already know this, and you probably know which of your devices are SCSI
devices! For more information, see the SCSI How-To.

Even the oldest systems can accept two devices on the hard disk
controller, so you can still install both hard disks at the same time.
However, if you already have another device installed in addition to
your hard disk (for example, if you have both a hard disk and a CD-ROM
drive), you'll have to remove the other device to be able to install the
old hard disk and the new hard disk at the same time.

You must configure the disks as "master" or "slave" by installing the
disks' jumpers as appropriate. You'll often find configuration
information on the disks themselves; if not, consult the manuals or the
disks' manufacturers.

You must also inform the BIOS of the disks' presence and of their
"geometry". Usually, you enter the BIOS setup programme by pressing a
key during the system boot-up. Here's what to do for some common BIOSes:

Acer notebooks: F2 key during Power-On Self-Test (POST)

American Megatrends (AMI): Del key during Power-On Self-Test

Award: Del, or Ctrl-Alt-Esc

Compaq: F10 key after the square appears in the top right corner
of the screen during boot-up

Dell: Ctrl-Alt-Enter

DTK: Esc key during Power-On Self-Test

IBM Aptiva 535: F1 while the square with the wavy lines is
displayed in the upper right corner during power-on
[Does this also apply to other Aptiva models?]

IBM PS/2: Ctrl-Alt-Del, then Ctrl-Alt-Ins when the cursor is in
the top right corner

Mr. BIOS: Ctrl-Alt-S during Power-On Self-Test

Packard Bell: For some models, F1 or F2 key during Power-On
Self-Test

Phoenix: Ctrl-Alt-Esc, or Ctrl-Alt-S, or Ctrl-Alt-Enter

Many older systems require an Installation or Reference Disk.

(We're interested in receiving information on other BIOSes to add them
to this list.)

Reboot the system and login as root. If you use the "su" command to
become the user root, use "su -", with the hyphen option.

2. Unmount non-Linux partitions and network drives
==================================================

Some people like to mount partitions from other operating systems (DOS,
Windows, OS/2, etc.) so they can use them under Linux. These partitions
must be created and copied under their own operating system, and you
should unmount them before copying your Linux partition. For example, if
you have a DOS partition mounted at /dos, you must unmount it with this
command:

umount /dos

Note that the command is "umount", without the first letter "n" in the
word "unmount".

You should also unmount network drives.

3. Partition the new disk
=========================

Use this command to partition the new disk:

fdisk /dev/hdb

EIDE devices are identified as hda, hdb, hdc, and hdd in the /dev
directory. Partitions on these disks can range from 1 to 16 and are also
in the /dev directory. For example, /dev/hda4 refers to partition 4 on
hard disk a (first EIDE hard disk).

SCSI devices are listed as devices sda, sdb, sdc, sdd, sde, sdf, and sdg
in the /dev directory. Similarly, partitions on these disks can range
from 1 to 16 and are also in the /dev directory. For example, /dev/sda3
refers to partition 3 on SCSI disk a (first SCSI hard disk).

For Linux partitions with the ext2 file system, use system ID 83. For
swap partitions, use system ID 82.

For more information on partitioning, see the Installation How-To and
the Partitioning Mini How-To.

If your new disk has over 1024 cylinders, see the Large Disk Mini
How-To. In brief, you should install all files required to boot Linux
within the first 1024 cylinders. One way to do this is to create a small
partition (5 Mb or so) just for the /boot directory at the beginning of
the disk. (Slackware only: The kernel is at /vmlinuz rather than
/boot/vmlinuz, so you should put both the / directory and the /boot
directory in this partition.)

Partitions for systems other than Linux should be created using their
own fdisk or equivalent command rather than with Linux's fdisk.

4. Format the new disk
======================

Use the following command to format Linux partitions using ext2fs on the
new disk:

mkfs.ext2 /dev/hdb1

To check the disk for bad blocks (physical defects), add the -c option
just before "/dev/hdb1".

If the new disk will have more than one Linux partition, format the
other partitions with "mkfs.ext2 /dev/hdb2", "mkfs.ext2 /dev/hdb3", and
so on. Add the -c option if desired.

(Note: With older distributions, the command "mkfs -t ext2 -c /dev/hdb1"
didn't check for bad blocks under any of Red Hat, Debian or Slackware,
contrary to what the man page stated. This has now been fixed.)

To format a swap partition, use this command:

mkswap /dev/hdb1

Again, you can add the -c option before "/dev/hdb1" to check for bad
blocks.

5. Mount the new disk
=====================

Create a directory where you'll mount the new disk, for example
/new-disk, and mount it there:

mkdir /new-disk
mount -t ext2 /dev/hdb1 /new-disk

If the new disk will have more than one Linux partition, mount them all
under /new-disk with the same organization they'll have later.

Example: The new disk will have four Linux partitions, as follows:

/dev/hdb1: /
/dev/hdb2: /home
/dev/hdb3: /var
/dev/hdb4: /var/spool

Mount the four partitions under /new-disk as follows:

/dev/hdb1: /new-disk
/dev/hdb2: /new-disk/home
/dev/hdb3: /new-disk/var
/dev/hdb4: /new-disk/var/spool

You must create the mount points for each "level" before you mount the
partitions at that level. Example:

mkdir /new-disk [1st level]
mount -t ext2 /dev/hdb1 /new-disk

mkdir /new-disk/home [2nd level]
mount -t ext2 /dev/hdb2 /new-disk/home

mkdir /new-disk/var [2nd level also]
mount -t ext2 /dev/hdb3 /new-disk/var

mkdir /new-disk/var/spool [3rd level]
mount -t ext2 /dev/hdb4 /new-disk/var/spool

If you've created a mount point at /new-disk/tmp, you'll need to correct
the directory's permissions to let all users access it:

chmod 1777 /new-disk/tmp

6. Copy the files from the old disk to the new disk
===================================================

You might want to go to single-user mode before starting to copy the
disk, in order to shut down the system daemons and preserve the state of
the logs, and to prevent users from logging in:

/sbin/telinit 1

When copying the hard disk, you want to copy all directories and files,
including links.

However, you *don't* want to copy the directory /new-disk, since this
would copy the new disk to itself!

Furthermore, you want to create the /proc directory on the new disk, but
you don't want to copy its contents: /proc is a "virtual" file system
and doesn't have any actual files, but rather contains information on
the processes running on the system.

Here are four different ways to copy the old disk to the new one. This
may take quite a while, especially if you have a large disk or little
memory. You can expect to be able to copy 10 Mb per minute, and possibly
much more.

You can follow the copy's progress by using the command "df" from
another terminal. Try "watch df" or "watch ls -l /new-disk" to see a
report updated every two seconds; press Ctrl-C to end the display. Be
aware that running the "watch" programme itself will slow down the
copying.

a) cp -ax / /new-disk

This is the simplest method, but will only work if your original
Linux system is on a single disk partition.

The -a option preserves the original system as much as possible.
The -x option limits cp to a single file system; this is
necessary to avoid copying the /new-disk and /proc directories.

(SuSE only: With this method only, you must also create the
directory /dev/pts on the new disk. Use the command "mkdir
/new-disk/dev/pts".)

(Note: When using the -x option, recent versions of cp will
create the directories /new-disk/new-disk and /new-disk/proc,
although the directories will be empty. If these directories are
created, you should delete /new-disk/new-disk, and keep
/new-disk/proc.)

b) cd / && echo cp -a `/bin/ls -1Ab |
egrep -v "^new-disk$|^proc$"` /new-disk | sh

(write this all on one line)

This goes to the root directory and then copies all files and
directories except /new-disk and /proc to /new-disk. Note that
the first option after ls is the number 1, not the letter L!

This command should work in all circumstances.

c) (cd / && tar cpf - . --exclude new-disk --exclude proc) |
(cd /new-disk && tar xpf -)

(write this all on one line)

This goes to the root directory, "tars" everything except
/new-disk and /proc, switches to /new-disk and "untars"
everything there. Note that there must not be a slash before or
after the names of the directories in the --exclude options.

(Note: The option -l doesn't work here, since tar will still
re-create the directories /new-disk and /proc even though it
doesn't copy their contents. Therefore, tar's -l option doesn't
have the same behaviour as the -x option on older versions of
cp.)

This method is somewhat slower than the others.

d) cp -a /bin /boot /dev /etc /home /lib /lost+found
/mnt /root /sbin /tmp /usr /var /new-disk

(write this all on one line)

The last directory, /new-disk, is the destination for the cp
command. All the other directories are the sources. Therefore,
we're copying all the directories we're listing to /new-disk.

With this method, you simply list yourself the directories you
want to copy. Here we listed all the directories except
/new-disk and /proc. If you can't use the other methods for any
reason, you can always use this command to manually specify the
directories you want to copy.

With this method only, if there are any files in the root
directory itself, you need another command to copy them. In
particular, this is required with Debian and Slackware, since
these distributions put files in the root directory:

cp -dp /* /.* /new-disk

After using any of these four methods, you must also create the /proc
directory on the new disk, if it doesn't already exist:

mkdir /new-disk/proc

At this point, you may verify the file structure on the new disk, if you
wish:

umount /new-disk
fsck.ext2 -f /dev/hdb1
mount -t ext2 /dev/hdb1 /new-disk

If the new disk has more than one partition, you must unmount them from
the "bottom up" before running fsck.ext2: in the example mentioned
above, you'd first unmount the 3rd level partitions, then the 2nd level
partitions, and then the 1st level partition.

You may also compare the two disks, to ensure that the files were copied
properly:

find / -path /proc -prune -o -path /new-disk -prune -o -xtype f
-exec cmp {} /new-disk{} \;

(write this all on one line)

(Slackware only: A basic Slackware installation ("A" series only)
doesn't include the "cmp" command, so you won't be able to run this
command if you have only installed the basic files. The "cmp" command is
in the "AP1" series.)

This will only compare regular files, not character or block special
files (in the /dev directory), sockets, etc., since the "cmp" command
doesn't work properly with these. We would welcome suggestions on how to
verify these "special" files.

7. Modify /new-disk/etc/fstab as appropriate
============================================

If your new disk doesn't have the same partitions or organization as the
old disk, modify the file /new-disk/etc/fstab on the new disk as
appropriate.

Make sure that the disk partitions (first column) correspond to the
organization you'll have with the new disk, once the old disk has been
removed, and that you're only mounting one partition at "/" as shown in
the second column.

For more information on the format of the file /etc/fstab, see the Linux
System Administrator's Guide, section 4, under "Mounting and
unmounting".

For swap partitions, use a line similar to this one:

/dev/hda1 swap swap defaults 0 0

8. Prepare LILO to boot the new disk
====================================

(Thanks to Rick Masters for helping with this.)

We're assuming that LILO is installed on the hard disk's Master Boot
Record (MBR); this seems to be the most common configuration. You want
to install LILO on what's presently the second hard disk but will become
the first hard disk.

Edit the file /new-disk/etc/lilo.conf as follows:

disk=/dev/hdb bios=0x80 # Tell LILO to treat the second
# disk as if it were the first
# disk (BIOS ID 0x80).
boot=/dev/hdb # Install LILO on second hard
# disk.
map=/new-disk/boot/map # Location of "map file".
install=/new-disk/boot/boot.b # File to copy to hard disk's
# boot sector.
prompt # Have LILO show "LILO boot:"
# prompt.
timeout=50 # Boot default system after 5
# seconds. (Value is in tenths of
# seconds.)
image=/new-disk/boot/vmlinuz # Location of Linux kernel. The
# actual name may include a version
# number, for example
# "vmlinuz-2.0.35".
label=linux # Label for Linux system.
root=/dev/hda1 # Location of root partition on
# new hard disk. Modify this as
# appropriate for your system.
# Note that you must use the name
# of the future location, once the
# old disk has been removed.
read-only # Mount partition read-only at
# first, to run fsck.

(Slackware only: Use "image=/new-disk/vmlinuz".)

If you're using a SCSI hard disk, you may have to add a line with
"initrd". See your existing file /etc/lilo.conf.

Install LILO on the new disk:

/sbin/lilo -C /new-disk/etc/lilo.conf

The -C option tells LILO what configuration file to use.

9. Make a boot diskette (optional)
==================================

If you wish, you can make a boot diskette, in case you run into problems
when trying to boot the new disk.

Insert an empty diskette, format it, create a file system on it and
mount it:

fdformat /dev/fd0H1440
mkfs.ext2 /dev/fd0
mount -t ext2 /dev/fd0 /mnt

(Debian only: With Debian 2.x, use "/dev/fd0u1440" instead of
"/dev/fd0H1440". With Debian 1.x, use "/dev/fd0h1440", with a lower case
"h".)

(Debian only: With Debian 2.x, use "superformat" instead of "fdformat".
You can ignore the error "mformat: command not found". With Debian 1.x,
if you don't have the command "fdformat", you can omit it if the floppy
is already formatted. In this case, you should check the diskette for
bad blocks by adding "-c" after the "mkfs.ext2" command.)

(Slackware only: Use "/dev/fd0u1440" instead of "/dev/fd0H1440". With
older versions, try "/dev/fd0h1440", with a lower case "h".)

(SuSE only: Use "/dev/fd0u1440" instead of "/dev/fd0H1440".)

Copy all files in /boot to the diskette:

cp -dp /boot/* /mnt

(Red Hat only: If the /boot directory contains both vmlinux and vmlinuz
files (note the difference in the last letter), you only need to copy
the vmlinuz files to the boot diskette. They are the same as the vmlinux
files, except that they're compressed to save space.)

(Slackware only: Copy the file /vmlinuz to the boot diskette; use the
command "cp /vmlinuz /mnt".)

Create a new file /mnt/lilo.conf as follows:

boot=/dev/fd0 # Install LILO on floppy disk.
map=/mnt/map # Location of "map file".
install=/mnt/boot.b # File to copy to floppy's
# boot sector.
prompt # Have LILO show "LILO boot:"
# prompt.
timeout=50 # Boot default system after 5
# seconds. (Value is in tenths of
# seconds.)
image=/mnt/vmlinuz # Location of Linux kernel on
# floppy. The actual name may
# include a version number, for
# example "vmlinuz-2.0.35".
label=linux # Label for Linux system.
root=/dev/hda1 # Location of root partition on
# new hard disk. Modify this as
# appropriate for your system.
# Note that you must use the name
# of the future location, once the
# old disk has been removed.
read-only # Mount partition read-only at
# first, to run fsck.

Install LILO on the boot diskette:

/sbin/lilo -C /mnt/lilo.conf

The -C option tells LILO what configuration file to use.

Unmount the diskette:

umount /mnt

10. Remove the old disk
=======================

Shut down the system and remove the old disk. Remember to modify the
disk jumpers and the BIOS information to reflect the changes.

11. Reboot the system, modify LILO configuration file
=====================================================

Reboot the system. If you have problems, you can use the boot diskette
you just make. To do so, you may have to modify your BIOS's boot-up
sequence to "A:, C:".

You should modify the file /etc/lilo.conf in case you later want to run
LILO again. Here's an example of how the file can look:

boot=/dev/hda # Install LILO on first hard
# disk.
map=/boot/map # Location of "map file".
install=/boot/boot.b # File to copy to floppy's
# boot sector.
prompt # Have LILO show "LILO boot:"
# prompt.
timeout=50 # Boot default system after 5
# seconds. (Value is in tenths of
# seconds.)
image=/boot/vmlinuz # Location of Linux kernel. The
# actual name may include a version
# number, for example
# "vmlinuz-2.0.35".
label=linux # Label for Linux system.
root=/dev/hda1 # Location of root partition on
# new hard disk. Modify this as
# appropriate for your system.
read-only # Mount partition read-only at
# first, to run fsck.

(Slackware only: Use "image=/vmlinuz".)

Acknowledgements:
=================

Thanks to Scott Christensen, Frank Damgaard, Alexandre Fornieles, David
Fullerton, Jerry Gaines, Chris Gillespie, Nicola Girardi, Per Gunnar
Hansoe, Richard Hawes, Ralph Heimueller, Gerald Hermant, Andy
Heynderickx, Paul Koning, Hannu Liljemark, Claes Maansson, Rick Masters,
Jason Priebe, Josh Rabinowitz, Douglas Rhodes, Valentijn Sessink, Kragen
Sitaker, Stephen Thomas, and Gerald Willman.

This document may be translated into any language. If you do so, please
send a copy of the translation to Konrad Hinsen
<[email protected]>.