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