|Revision v1.40||2002-01-10||Revised by: rjt|
|Added description and link to cdtower shell script.|
|Revision v1.30||2002-01-08||Revised by: rjt|
|Many additions and changes to markup in DocBook XML source and fix pubdate data.|
|Revision v1.01||2002-01-07||Revised by: rjt|
|Updated for 2.4 kernels. Added more References and links. Convert to DocBook XML 4.1.2 Change License from LDP boilerplate to GFDL.|
|Revision v1.00||2000-09-23||Revised by: rjt|
|Conversion from Linuxdoc SGML to DocBook v3.1 SGML|
|Revision v0.10||2000-09-01||Revised by: rjt|
|Conversion to Linuxdoc SGML from text/html, added kerneltweak (addloops) section|
|Revision v0.01||2000-08-18||Revised by: rjt|
|First version released in text and html.|
With disk space becoming less expensive (100GB Western Digital 7200rpm available for US $195 in January 2002), it is 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 Pentium 200 with 64MB RAM, using one of these large drives.
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.
The commands and utilities needed to setup your own CD Server are already included in most (if not all) Linux distributions.
A Linux Distribution (This HOWTO uses Linux-Mandrake for the examples)
dd - Converts and copies a file (a standard Unix command)
mount - Mounts and Unmounts filesystems (a standard Unix command)
Samba - A Windows SMB/CIFS fileserver for Unix
NFS (optional for Unix) - Network File System (included in Linux distributions)
Netatalk (optional for Macs) - A package that lets a Unix machine supply Appletalk print and file services on a LAN.
Previous to the 2.4 kernels, the Linux-Mandrake distribution I was using only had support for 8 loop devices compiled into the kernel (see Section 3 to increase this number). At that time, you were only be able to share 8 CD's on a network with that default value, and to share more than 8, the loop block driver source code (loop.c) needed to be modified and a new kernel compiled.
With the 2.4 kernels, that is no longer required. You can now set the number of loop devices dynamically via the max_loop module parameter, or by passing max_loop=[1-255] to the kernel on boot.
SMB HOWTO by: David Wood, dwood (at) plugged.net.au. Part of the Linux Documentation Project. This document describes how to use the Server Message Block (SMB) protocol, also called the Session Message Block, NetBIOS or LanManager protocol, with Linux using Samba.
Using Samba by: Robert Eckstein, David Collier-Brown, Peter Kelly 1st Edition November 1999, O'Reilly and Associates, Inc. ISBN 1-56592-449-5,
The Linux CD-ROM HOWTO by: Jeff Tranter, tranter (at) pobox.com. Part of the Linux Documentation Project. How to install, configure, and use CD-ROM drives under Linux. It lists the supported hardware and answers a number of frequently asked questions. This HOWTO also gives some information on using multi-platter CD-ROM drives with Linux.
CD-Writing HOWTO by: Winfried Trümper, winni (at) xpilot.org. Part of the Linux Documentation Project. This document explains how to write CD-ROMs under Linux. This HOWTO also includes information on making 1:1 image copies of CD-ROMs.
CDServer-HOWTO, Copyright © 2000-2002, by Randolph J. Tata, All Rights Reserved
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts and no Back-Cover Texts. A copy of the license is included in Appendix A entitled "GNU Free Documentation License".
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.
As always, check the revision history at the top of this document.
DocBook XML source for this document is available. Any additions/changes should be made to the DocBook XML source, not derivative formats.
This documents home page is at the CDServer-HOWTO site page in case you need the latest version, or there is a problem with the page format you are viewing.
My thanks go the readers of this HOWTO and those willing to share their experiences and knowledge with me. 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|
|Amar Chaouche||achaouche (at) linbox.com||mount unhide option|
|Giblhauser Carl Michael||mike (at) bawb.bmlf.gv.at||runoutblock i/o errors|
|Monte Milanuk||milanuk (at) yahoo.com||nfs help|
|Paul A. Sand||pas (at) unh.edu||loop module option max_loop|
|Tony Melia||Tony.Melia (at) downsmicro.com.au||max_loop kernel boot parameter|
|Richard Black||Richard.Black (at) compaq.com||more info and mknod script|
|Bradley Wendelboe||krakken (at) icehouse.2y.net||cdtower shell script|
|James Mumm||dart (at) windeath.2y.net||cdtower shell script|
Korean (html and sgml) at http://www.ibiblio.org/pub/Linux/docs/HOWTO/translations/korean/
If you have the capacity it would be nice to make the CDServer-HOWTO available in a number of formats and languages.
If you've translated this document, please send to me:
Your name, email address, the language and URL to the translated document (preferred).
Or an email attachment of the work.
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.
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=mndrk81.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.
If you see i/o errors, they will most likely be due to the lead-in and lead-out runoutblocks on the CD. If the number of records in and number of records out do not match you may have a problem, otherwise the image will most likely be alright, but you can never know if the errors happened while reading the ISO part of the CD or not (due to dust or scratches on the CD).
Other utilities to read CD's exist, like readcd or sdd.
More information about making 1:1 copies of CD's exists in the [CD-Writing-HOWTO], see Section 1.3.
My thanks to Giblhauser Carl Michael for the runoutblock information.
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 mndrk81
Now mount the ISO image file to this newly created directory
bash# mount -o loop,unhide -t iso9660 -r /home/image/mndrk81.iso /mnt/iso/mndrk81
The "-o loop" means use the option that mounts a file as a block device. The unhide option shows hidden files. The "-t iso9660" means that the file is in the iso9660 CD-ROM format. The "-r" means to mount read-only.
Thanks to Amar Chaouche for pointing out the unhide option for the mount command.
Now you can:
bash# cd mndrk81 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!)
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/mndrk81.iso /mnt/iso/mndrk81 iso9660 ro,loop,auto,unhide 0 0
You'll need to have Samba installed and working to perform the next steps (that's outside the scope of this instruction, see Section 1.3). 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.
[mndrk81] comment = Mandrake Linux 8.1 path = /mnt/iso/mndrk81 public = yes writable = no
Then, at your MS-DOS Prompt, mount it with the following command:
C:\> net use m: \\yourlinuxmachine\mndrk81
The Samba smb.conf file stanzas presented here are simplified, and not secure. Many more options exist for a Samba share which limit who can mount the shares, control how user authentication is performed, and whether the share is even browseable through Network Neighborhood on the Windows machines.
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,nohide,all_squash)
The nohide option will allow you to mount a parent directory, without explicitly mounting all exported subdirectories beneath it.
Now try running:
bash# exportfs -r
This should re-export everything in your /etc/exports file.
Now, when typing "showmount -e yourlinuxmachine" you should see that the /mnt/iso directory is included in the exports list.
Newer Linux kernels (2.4) allow you to add more loop devices easily by editing /etc/modules.conf or through the use of a boot parameter.
Older kernels (2.2 ?) only had support for 8 loop devices compiled into the kernel. In short, you were only able to share 8 CD's on a network with this default value. In order to support more than that default, you needed to modify the kernel source and recompile a new kernel.
Use the following methods to determine which version of the kernel you are running.
bash# uname -a
bash# cat /proc/version
Current kernels allow you to set the number of loop devices supported without recompiling the kernel. One of these methods is to add an options line to /etc/modules.conf. This method will only work if your loop support has been configured as a loadable kernel module (which is how most major Linux distributions come preconfigured now).
Edit /etc/modules.conf and add the following line.
options loop max_loop=64
After making the above change, simply reboot. Or you can try to use rmmod and insmod to make the change on the fly - but this will not work if you currently have any loop devices mounted (you'll get an error saying loop: Device or resource busy).
If you do not have an /etc/modules.conf file, your module configuration file may be called /etc/conf.modules (this name is now deprecated).
Continue with Section 3.4.
Thanks to Paul A. Sand for pointing out the /etc/modules.conf option.
If your loop support has been compiled directly into the kernel (in other words, it is not loaded as a module), you can append the number of loop devices you would like to support at the linux boot prompt.
boot: linux max_loop=64
Or, if you are using LILO, you can edit your linux boot stanza in /etc/lilo.conf and add/modify the append= line. Here is an example stanza showing append= (note: only add or modify the append line, don't change your whole stanza to look like this one or your system may not boot). For more information about LILO, consult the LILO mini-HOWTO at http://www.linuxdoc.org/HOWTO/mini/LILO.html.
image=/boot/vmlinuz label=linux root=/dev/hdb5 initrd=/boot/initrd.img append=" max_loop=64" vga=788 read-only
After changing /etc/lilo.conf, you need to run the lilo command for your changes to take effect.
bash# lilo Added linux * Added linux-nonfb Added failsafe Added windows Added floppy
Next restart your system. After your system restarts, you can check your boot command line by typing the following:
bash# cat /proc/cmdline
I am not sure if the loop module (compiled as a module) reads /proc/cmdline when the module is loaded, and therefore may not need an options line /etc/modules.conf. It's possible that it can (and if it doesn't, it should). To summarize: I have not tested this.
Continue with Section 3.4.
Thanks to Tony Melia for the boot prompt info.
If you have an older kernel (v. 2.2) or if you are completely comfortable recompiling the kernel, you can increase the number of loop devices supported by editing 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 GNU 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 or consult The Linux Kernel HOWTO.
Continue with Section 3.4.
You should check how many /dev entries you have for loop devices.
bash# ls -l /dev/loop*
The mknod command creates the devices in the /dev directory. 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 /dev/loop0 through /dev/loop7. To create the /dev/loop8 device, use the following command (subsitute the appropriate number you need for both the "8's" in the example below).
bash# mknod -m660 /dev/loop8 b 7 8
Check Owner/Group & Permissions on the new file (using ls -l). You can change the owner and group with the following command:
bash# chown root.disk /dev/loop8
You can change the permissions using the following command:
bash# chmod 666 /dev/loop8
Be sure to check the suggested reading in Section 1.3.
I finally had to create this section - Frequently Asked Questions. Although, I sometimes think it should be called Frequently Answered Questions (at least I try to answer them all).
A: In a word - Yes.
There is nothing to keep you from doing that. However I'm not sure which arguments you would have to use with tar and which options to include in the SAMBA stanzas. Also, there could be problems with file name mangling (case sensitivity, spaces in file names), file attributes (read-only), etc. If anyone is doing this successfully, please send me examples of the commands you used for copying the contents of the CD, and your SAMBA stanzas for the shares.
Here's some commands you can use to copy the contents:
bash# cd /home bash# mkdir image bash# cd image bash# mkdir mndrk81 bash# mount /mnt/cdrom bash# cd /mnt/cdrom bash# tar cvf - . | (cd /home/image/mndrk81; tar xvf -)
Thanks to Giblhauser Carl Michael for this info
Bradley Wendelboe and James Mumm wrote a shell script called CDTower - see Section 4.2.2 to download it.
I have no independent test results of this script - use at your own risk.
A: Not yet. However there is much interest in this.
Tony Melia [Tony.Melia (at) downsmicro.com.au] has announced that he is 60% complete with a web interface, i.e. sucking CD's in, creating extra /dev/loop entries and seeing what space the CD's are taking up.
I am planning on writing a module for Webmin to automate this process. That project is currently hosted on SourceForge at http://sourceforge.net/projects/opencdserver
This section is devoted to instructional materials that others have written or have sent to me.
Richard Black (Compaq) has some good pages about Saving CD-ROM's to files and mounting them in Red Hat Linux.
Linux Loop Devices - This page also includes the script below for creating many loop device nodes at once in /dev.
Device nodes are required to access the loop devices. You already have loop0 - loop7. You can run the following loop to create the rest of the nodes (loop8 - loop255). You can type all of the following lines of code on one single line if you leave off the trailing "\" characters. C=8; echo; echo "Creating loop device nodes."; \ while [ $C -lt 256 ]; do mknod /dev/loop$C b 7 $C; \ echo -n .; C=`expr $C + 1`; done; echo; Note: the quoting around the expr section are called backtick's and they are located with the tilde character ("~") in the upper left hand corner of the keyboard. The character is not a single quote.
Thanks to Richard Black for permission to add this info and for linking back to this document.
A script to automate the creation of ISO images and share them via Samba
by Bradley Wendelboe [krakken (at) icehouse.2y.net] and James Mumm [dart (at) windeath.2y.net]
This software is covered under the GPL See http://www.gnu.org/copyleft/gpl.html for details.
I have no independent test results of this script - use at your own risk.
Thanks to Bradley Wendelboe for forwarding this script to me.
These are things I'm currently looking into, trying to figure out, or planning to get done.
Make more scripts available that others have sent to me, either within this howto, or by hosting them and linking to them from this document.
Sharing CD's to Apple and Netware clients (Appletalk and IPX).
Compressed ISO Images.
Changing CD Shares on the fly (hopefully transparent to users).
Adding a module to Webmin to automate the CDServer process.
Distribution specific instructions.
I have a volunteer for a German translation, hopefully it will be done soon.
Version 1.1, March 2000
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