
CDServer-HOWTO

Randolph Tata

   randy@talcon.com
   
   v1.00, 23 September 2000
   Revision History
   Revision v1.00 23 September 2000 Revised by: rjt
   Conversion from linuxdoc sgml to DocBook v3.1
   Revision v0.10 1 September 2000 Revised by: rjt
   Conversion to linuxdoc sgml from text/html
   Revision v0.01 18 August 2000 Revised by: rjt
   First version released in text and html. Still need to add section on
   kernel modifications and creating more loop devices.
   
   The CD Server HOWTO describes the steps and commands you can use to
   setup your own CD Server using Linux and some built-in Unix commands
   along with other freely available software packages. The CD Server can
   then share the CD's via the network to Windows and/or other client
   machines.
     _________________________________________________________________
   
   Table of Contents
   1. [1]Introduction
          
        1.1. [2]Intended Audience
        1.2. [3]Things You'll Need
        1.3. [4]Suggested Reading
        1.4. [5]Copyright
        1.5. [6]Disclaimer
        1.6. [7]News
        1.7. [8]Credits
        1.8. [9]Translations
                
   2. [10]Procedure
          
        2.1. [11]Creating the ISO Images
        2.2. [12]Mounting the ISO Images
        2.3. [13]Mounting the Image upon System Restart
        2.4. [14]Sharing it on a Windows Network using Samba
        2.5. [15]Sharing the Images on a Unix network using NFS
                
   3. [16]Adding Support for More Loop Devices
          
        3.1. [17]Tweaking the Kernel
        3.2. [18]Creating the Loop Devices in /dev
                
1. Introduction

   With disk space becoming less expensive (30GB IBM 7200rpm for $160 in
   08/2000), it is now viable to use an Open Source software-based CD
   Server solution, instead of paying $800-$4,000 for a software,
   thin-server, or CD Jukebox solution.
   
   I've setup my CD Server on a P120 with 64MB RAM, using one of these
   large drives.
     _________________________________________________________________
   
1.1. Intended Audience

   This HOWTO is specifically directed toward System Administrators and
   uses Linux for the examples. It should work with other flavors of Unix
   provided that they have a loop device or a method of mounting a CD
   image file within the directory tree as a block device using the
   iso9660 file system.
     _________________________________________________________________
   
1.2. Things You'll Need

   The commands and utilities needed to setup your own CD Server are
   already included in most (if not all) Linux distributions.
   
     * Linux Distribution (This HOWTO uses [19]Linux-Mandrake for the
       examples)
     * dd - Converts and copies a file (a standard Unix command)
     * mount - Mounts and Unmounts filesystems (a standard Unix command)
     * [20]Samba - A Windows SMB/CIFS fileserver for Unix
     * NFS (optional) - Network File System (usually included in Linux
       distributions)
       
   Caveats
          The Linux-Mandrake distribution I'm using (7.0), only has
          support for 8 loop devices compiled into the kernel (see
          [21]Section 3 to increase this number). In short, you'll only
          be able to share 8 CD's on a network at most with this default
          value, to share more than 8, you'll need to do a little more
          work.
     _________________________________________________________________
   
1.3. Suggested Reading

   [22]Using Samba by: Robert Eckstein, David Collier-Brown, Peter Kelly
   1st Edition November 1999, O'Reilly and Associates, Inc. ISBN
   1-56592-449-5,
     _________________________________________________________________
   
1.4. Copyright

   CDServer-HOWTO, Copyright (c) 2000, Randolph Tata, All Rights Reserved
   
   Please freely copy and distribute (sell or give away) this document in
   any format. It's requested that corrections and/or comments be
   fowarded to the document maintainer ([23]Randolph Tata). You may
   create a derivative work and distribute it provided that you:
   
     * Send your derivative work (in the most suitable format such as
       sgml) to the LDP ([24]Linux Documentation Project) or the like for
       posting on the Internet. If not the LDP, then let the LDP know
       where it is available.
     * License the derivative work with this same license or use GPL.
       Include a copyright notice and at least a pointer to the license
       used.
     * Give due credit to previous authors and major contributors.
       
   If you're considering making a derived work other than a translation,
   it's requested that you discuss your plans with the current
   maintainer.
     _________________________________________________________________
   
1.5. Disclaimer

   Use the information in this document at your own risk. I disavow any
   potential liability for the contents of this document. Use of the
   concepts, examples, and/or other content of this document is entirely
   at your own risk.
   
   All copyrights are owned by their owners, unless specifically noted
   otherwise. Use of a term in this document should not be regarded as
   affecting the validity of any trademark or service mark.
   
   Naming of particular products or brands should not be seen as
   endorsements.
   
   You are strongly recommended to make a backup of your system before
   major installation and should make backups at regular intervals.
     _________________________________________________________________
   
1.6. News

   This is the first sgml release (version 1.00). [25]SGML source for
   this document is available. Any additions/changes should be made to
   the sgml source, not derivative formats.
   
   This documents home page is at the [26]Open CD Server Project site
   page in case you need the latest version, or there is a problem with
   the page format you are viewing.
   
   If you have the capacity it would be nice to make the CDServer-HOWTO
   available in a number of formats and languages.
     _________________________________________________________________
   
1.7. Credits

   In this version I have the pleasure of acknowledging
   
Mark F. Komarinski    markk (at) linuxdoc.org         LDP Author Guide
Jorge Godoy           godoy (at) metalab.unc.edu      LDP Author Guide
David C. Merrill      dcmerrill (at) mindspring.com   LDP Author Guide
Stein Gjoen           sgjoen (at) nyx.net             HOWTO-Template
Gregory Leblanc       gleblanc (at) cu-portland.edu   HOWTO-Template
Greg Ferguson         gferg (at) sgi.com              HOWTO-Template
     _________________________________________________________________
   
1.8. Translations

   No Translations yet.
   
   Any comments or suggestions can be mailed to my email address at
   [27]Talcon Information Systems: <[28]randy@talcon.com>.
     _________________________________________________________________
   
2. Procedure

   Summary of Steps
   
     * Create a large partition to hold the CD Image Files.
     * Copy the CD to an image file using the "dd" command.
     * Mount the CD image file within the directory tree.
     * Share the directory on the network using Samba, NFS, etc.
     _________________________________________________________________
   
2.1. Creating the ISO Images

   Choose (or create) a file system with the largest available disk space
   on it. Keep in mind that CD-ROM's can hold around 640MB of data, so if
   you want to share 8 full CD's on your network, you'll need 5.1GB of
   space available.
   
Login as root or "su" to root.

bash# df -h

Filesystem            Size  Used Avail Use% Mounted on
/dev/hda5             1.4G   82M  1.3G   6% /
/dev/hda1              15M  827k   14M   6% /boot
/dev/hda7             2.4G 1008M  1.3G  43% /usr
/dev/hda8            23.6G 11.7G 11.7G  50% /home

   Here the /home filesystem has the most available space, so it is the
   most suitable filesystem to use for dumping the CD images to.
   

bash# cd /home
bash# mkdir image
bash# cd image

   Now, copy the CD to an iso image. You must know the device name of
   your CD-ROM drive (usually /dev/cdrom, it could be /dev/scd0 for SCSI
   CD-ROM's) I'll use the Mandrake distribution CD-ROM as an Example:
   
bash# dd if=/dev/cdrom of=mndrk71.iso

   The "if=" is the input file, the "of=" is the output file. You should
   see a message stating the number of records in and number of records
   out (hopefully with no i/o errors).
     _________________________________________________________________
   
2.2. Mounting the ISO Images

   The next step is to mount the iso image file. Let's create a directory
   under /mnt to place the mounted file.
   
bash# cd /mnt
bash# mkdir iso
bash# cd iso
bash# mkdir mndrk71

   Now mount the ISO image file to this newly created directory
   
bash# mount -o loop -t iso9660 -r /home/image/mndrk71.iso /mnt/iso/mndrk71

   The "-o loop" means use the option that mounts a file as a block
   device. The "-t iso9660" means that the file is in the iso9660 CD-ROM
   format. The "-r" means to mount read-only.
   
   Now you can:
   
bash# cd mndrk71
bash# ls -al

   You should see a listing (ls) of the files and directories that are on
   the actual CD (only now they're inside the iso image file, and that's
   what you're currently looking at!)
     _________________________________________________________________
   
2.3. Mounting the Image upon System Restart

   Now that we've manually mounted the image, and made sure it works, an
   entry needs to made in the /etc/fstab file so that the image is
   remounted on the next system startup. It's important to make the entry
   AFTER the entry for the parent filesystem, e.g. /home (I use vim, but
   Emacs, Joe, Pico or Jed will work just as well):
   
bash# vim /etc/fstab

   After the line that looks like the following (or whichever filesystem
   you've placed your images):
   
/dev/hda8 /home ext2 defaults 1 2

   Insert the following line with your text editor:
   
/home/image/mndrk71.iso /mnt/iso/mndrk71 iso9660 ro,loop,auto 0 0
     _________________________________________________________________
   
2.4. Sharing it on a Windows Network using Samba

   You'll need to have Samba installed and working to perform the next
   steps (that's outside the scope of this instruction). If it's not yet
   installed, consult your Linux distribution's instructions for
   installing the Samba package. Or you can visit the Samba website at
   http://us1.samba.org/samba/samba.html for installation instructions,
   binaries, and/or the source code.
   
   To share your mounted CD's on a windows network, simply create a
   stanza in the /etc/smb.conf file similar to the following:
   
[cdimages]
  comment = All Shared CD Images
  path = /mnt/iso
  public = yes
  writable = no

   This will share all the subdirectories under the /mnt/iso directory on
   the network. To mount the share to a local drive (in this case the I:
   drive), bring up an MS-DOS Prompt on the Windows machine and type the
   following:
   
C:\> net use I: \\yourlinuxmachine\cdimages

   Each CD image will now appear as a subdirectory on the I: drive of
   your Windows machine.
   
   To mount ONLY the Mandrake CD image to a drive letter (we'll use M:,
   the root drive of which, will correspond exactly to the CD as if it
   was just inserted in the CD-ROM drive), create the following stanza in
   the /etc/smb.conf file.
   
[mndrk71]
  comment = Mandrake Linux 7.1
  path = /mnt/iso/mndrk71
  public = yes
  writable = no

   Then, at your MS-DOS Prompt, mount it with the following command:
   
C:\> net use m: \\yourlinuxmachine\mndrk71

   Note:
          The Samba smb.conf file stanzas presented here are simplified,
          and not entirely secure. Many more options exist for a Samba
          share which limit who can mount the shares, control how user
          authentication is performed, whether the share is even
          browseable through Network Neighborhood on the Windows
          machines.
     _________________________________________________________________
   
2.5. Sharing the Images on a Unix network using NFS

   Make sure that NFS is running and configured correctly on your Linux
   machine, then add the following to the /etc/exports file using your
   own preferred options:
   
# sample /etc/exports file
       /mnt/iso            (ro,insecure,all_squash)

   Now, when typing "showmount -e yourlinuxmachine" you should see that
   the /mnt/iso is included in the exports list.
     _________________________________________________________________
   
3. Adding Support for More Loop Devices

   The Linux-Mandrake distribution I'm using (7.0), only has support for
   8 loop devices compiled into the kernel. In short, you'll only be able
   to share 8 CD's on a network with this default value. To support more
   than the default, you'll need to follow this section. If you're new to
   Linux, you've going to learn some cool things by accomplishing this.
     _________________________________________________________________
   
3.1. Tweaking the Kernel

   To increase the number of loop devices supported by the kernel, you'll
   need to edit the /usr/src/linux/drivers/block/loop.c file.
   
   If you find that the kernel sources are not installed on your machine,
   you'll need to consult your Linux Distribution's documentation on how
   to install them (the Kernel Sources come with all distributions - it's
   part of the GPL licensing).
   
   Change the number in the following line to however many loop devices
   you'll need.
   
#define MAX_LOOP 16

   Compile the new kernel or module as the case may be. If you need some
   help getting started with this, read /usr/src/linux/README.
     _________________________________________________________________
   
3.2. Creating the Loop Devices in /dev

   The mknod command creates the devices in /dev. The loop devices have a
   major number of "7", and the minor numbers begin at "0". If your
   MAX_LOOP was defined as 8 in /usr/src/linux/drivers/block/loop.c, you
   should have loop0 thru loop7 in /dev. To create the /dev/loop8 device,
   use the following command (subsitute the appropriate number for the
   "8" in the example below).
   
mknod -m660 /dev/loop8 b 7 8

   Check Owner/Group & Permissions on the new file. You can change the
   owner and group with the following command:
   
chown root.disk /dev/loop8

   You can change the permissions using the following command:
   
chmod 666 /dev/loop8

References

   1. CDServer-HOWTO.html#INTRODUCTION
   2. CDServer-HOWTO.html#AUDIENCE
   3. CDServer-HOWTO.html#NEEDED
   4. CDServer-HOWTO.html#READING
   5. CDServer-HOWTO.html#COPYRIGHT
   6. CDServer-HOWTO.html#DISCLAIMER
   7. CDServer-HOWTO.html#NEWS
   8. CDServer-HOWTO.html#CREDITS
   9. CDServer-HOWTO.html#TRANSLATIONS
  10. CDServer-HOWTO.html#PROCEDURE
  11. CDServer-HOWTO.html#CREATEIMAGE
  12. CDServer-HOWTO.html#MOUNTIMAGE
  13. CDServer-HOWTO.html#SYSTEMRESTART
  14. CDServer-HOWTO.html#SHARING
  15. CDServer-HOWTO.html#NFS
  16. CDServer-HOWTO.html#KERNELTWEAK
  17. CDServer-HOWTO.html#EDITKERNEL
  18. CDServer-HOWTO.html#LOOPDEV
  19. http://www.linux-mandrake.com/
  20. http://www.samba.org/
  21. CDServer-HOWTO.html#KERNELTWEAK
  22. http://www.oreilly.com/catalog/samba/
  23. mailto:randy@talcon.com
  24. http://www.linuxdoc.org/
  25. CDServer-HOWTO.sgml
  26. http://talcon.com/opencdserver/
  27. http://www.talcon.com/
  28. mailto:randy@talcon.com
