Chip 1998 September/CHIP Eylül 1998.iso/Slackwar/docs/mini/Hard-Disk-Upgrade

Text File | 1997-03-16 | 16.4 KB | 489 lines

                         HARD DISK UPGRADE MINI HOW-TO

Yves Bellefeuille,
[e-mail]



   Version 1.0,
   31 January 1998
     _________________________________________________________________



   _How to copy a Linux system from one hard disk to another._
     _________________________________________________________________



   1. Install both disks on your system
   2. Unmount non-Linux partitions
   3. Partition the new disk
   4. Format the new disk
   5. Mount the new disk
   6. Copy the files from the old disk to the new disk
   7. Modify /etc/fstab as appropriate
   8. Prepare LILO to boot the new disk
   9. Remove the old disk
   10. Reboot the system, install LILO on the new disk
     _________________________________________________________________



   Recently, I replaced my small 249 Mb hard disk with a larger disk. I
   wanted to transfer my entire Linux system, including LILO, from the
   old disk to the new disk. This is how I did it.

   In the following explanation, I use "/dev/hda" to denote the "old"
   disk, and "/dev/hda1" means the old Linux partition. "/dev/hdb" means
   the "new" disk, and "/dev/hdb1" means the new Linux partition.

   Therefore, I'm assuming that Linux is on the first partition of the
   first disk. Modify this as appropriate for your set-up.

   This document is based on my own system, running Red Hat 4.2, and I've
   tested all the commands that follow with that distribution. I've also
   tested them under Debian 1.3.1 and Slackware 3.3, and I indicate a few
   differences to note if you're using those distributions.

   If the commands don't work properly on your system, please let me
   know, telling me what version of Linux 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:



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

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

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

     Many older systems require an Installation or Reference Disk.



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

   Reboot the system and login as root.
     _________________________________________________________________



2. Unmount non-Linux partitions



   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", with the first letter "n" missing
   from the word "unmount".
     _________________________________________________________________



3. Partition the new disk



   Use this command to partition the new disk:

     fdisk /dev/hdb



   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 (1 Mb or 2 Mb) 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 the new disk:

     mkfs.ext2 /dev/hdb1



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

   (Note: Contrary to what the man page states, the command "mkfs -t ext2
   -c /dev/hdb1" doesn't check for bad blocks under any of Red Hat,
   Debian or Slackware.)
     _________________________________________________________________



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


     _________________________________________________________________



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



   You want to completely reproduce the disk structure, 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. If you're as easily amused as I am, 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.
    1. 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.
    2. cd / && cp -a `/bin/ls -1A | egrep -v "^new-disk$|^proc$"`
       /new-disk



     (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.
    3. (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 cp's -x option.)

     This method is somewhat slower than the others.
    4. 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, here
     I'm copying all the directories I'm listing to /new-disk.

     With this method, you simply list yourself the directories you want
     to copy. Here I listed all my 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:

     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



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


#!/bin/sh
cd /
for file in `/bin/ls -1A | egrep -v '^new-disk$|^proc$'`
do
    find $file -xtype f -exec cmp \{\} /new-disk/\{\} \;
done



   (_Slackware only:_ A basic Slackware installation doesn't include the
   "cmp" or "diff" commands, so you won't be able to run this script if
   you have only installed the basic files.)

   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. I would welcome suggestions on how
   to verify these "special" files.
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7. Modify /etc/fstab as appropriate



   If your new disk doesn't have the same partitions or organization as
   the old disk, modify the file /etc/fstab on the new disk as
   appropriate. Remember that this file is currently located at
   /new-disk/etc/fstab.

   Make sure that the disk partitions in the 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.
     _________________________________________________________________



8. Prepare LILO to boot the new disk



   This is the most complicated step. I'm 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.
   It's clear that LILO can't _run_ from the second hard disk; however,
   LILO's documentation does anticipate that you might want to _install_
   LILO on the second hard disk, for example if the first hard disk will
   be removed:



     LILO can't be stored at any of the following locations:

     - on the second hard disk. (Unless for backup purposes, if the
     current first disk will be removed or disabled, or if some other
     boot loader is used, that is capable of loading boot sectors from
     other drives.)



   However, the documentation doesn't explain the proper way to install
   LILO on the second hard disk if the first hard disk will be removed,
   and I've concluded after many attempts that it isn't possible to
   install LILO directly onto the MBR of the second hard disk and have it
   work correctly the first time.

   Instead, I suggest the use of a boot diskette to boot the new hard
   disk the first time.

   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:_ The command "fdformat" is not included in a basic
   installation with Debian. If you don't have this command, you may 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.

   (_Debian and Slackware only:_ Use the command "fdformat
   /dev/fd0h1440", with a lower case "h".)

   Copy all files in /boot to the diskette:

     cp -dp /boot/* /mnt



   (_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.
    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.



   (_Debian only:_ In the "image" line, use the actual name of the Linux
   kernel. For example, with Debian 1.3.1, use "/mnt/vmlinuz-2.0.29".)

   Install LILO on the boot diskette:

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



   The -C option tells /sbin/lilo what configuration file to use.

   Unmount the diskette:

     umount /mnt



   and shut down the system.
     _________________________________________________________________



9. Remove the old disk



   After removing the old disk, remember to modify the disk jumpers and
   the BIOS information to reflect the changes.
     _________________________________________________________________



10. Reboot the system, install LILO on the new disk



   Reboot the system from the boot diskette you just made. To do so, you
   may have to modify your BIOS's boot-up sequence to "A:, C:".

   Make any necessary changes to the /etc/lilo.conf file, and run
   /sbin/lilo to install LILO on the new disk. With Debian, make sure
   that the "boot" line says "/dev/hda" rather than "/dev/hda1" or
   similar if you want to install LILO on the Master Boot Record.

   You can then try re-booting your system from your new hard disk to
   test if everything is working properly. If you run into any problems,
   you can still use the diskette you just made to boot your system.
     _________________________________________________________________

Acknowledgements



   Special thanks to _Dr Konrad Hinsen_ of the Institut de biologie
   structurale, Grenoble, France, who has been kindly acting as my
   personal Linux guru. Thanks also to _Frank Damgaard_, _Paul Koning_
   and _Josh Rabinowitz_, and to _Scott Christensen_ for alerting me to
   some particularities of the Slackware distribution.
     _________________________________________________________________