DVD-R: The Affordable Alternative to Tape Backup

Note, however, that DVD-R back-up is only a supplement to a mirror drive or RAID array, not a substitute. DVD backup is takes too much time to be a realistic day-to-day solution.

That said, you can send an offsite DVD-R backup set inexpensively via the mail or FedEx in a padded mailer, and you needn't worry about stray magnetic fields or other shipping damage. Try that with a hard drive or tape cartridge!

For this Recipe, I used a system with a 900-MHz Duron CPU, 7200-rpm 40-GB hard disk, and 4x Emprex DVD-R/RW drive. I assigned the DVD-R drive to Drive F: If you use other equipment, your times may vary. Also, feel free to substitute whatever drive letter is appropriate for your systems.

How to select a DVD drive

The tradeoff is speed vs. cost. A 4x unit will burn a DVD-R in about half an hour. This is an area where quality counts, so be inclined to spend a few bucks more on a name brand or higher speed drive.

Also, be sure to buy high-quality DVD discs. According to the FAQ provided by Usenet newsgroup rec.video.dvd, you should look for well-manufactured DVD-Rs with gold metal reflective backing and either phthalocyanine (clear) or azo (dark blue) dye for maximum archival longevity. After the purchase, storage conditions and handling are the main factors that determine longevity.

To learn more about caring for DVD discs, download this how-to article from the National Institute of Standards and Technology (NIST). The single-page summary provides enough information for most users. Provide copies to your customers with the computers you sell with DVD-R drives.

How to install a DVD drive

Good news, it's simple. Install a DVD drive just as you would any other IDE drive. The master/slave jumper selection is usually a single jumper on the back of the drive, clearly marked.

The software packaged with your drive will typically include DVD player software and a DVD burner software demo. It is not hard-disk backup software.

How to select a backup software package

For this Recipe, I used ZipBackup software to create backup sets spanned across multiple media, since I have well over 9 GB of data. ZipBackup has a major advantage over other backup programs I've used: It uses the standard ZIP file archive format. WinZip and other zip archive program can recover the files without the backup program if need be. The ZipBackup version discussed here is version 3.18.5. The demo version is free for 30 days; after that, it costs $39.95.

There are differences between DVD and hard-drive file structure. Since you want to recover your hard drive directory/file structure exactly, use a specialized backup package to prepare the files for burning. And use your installed DVD-burning software to burn those prepared backups to DVD.

Compressing large amounts of data is CPU/disk intensive, so speed counts. The software includes a compression slider that lets you trade compression level for time; the more compression you want, the more time it takes. Low levels of compression means more disks to burn. The optimum setting depends on specific characteristics of your system environment. My advice: Experiment.

Unless you know you have less than 9 GB to back up (medium compression), don't let ZipBackup burn directly to DVD-R. A backup program that is waiting for you to return to load disks is not compressing your files. For more than 9 GB, use the backup program to create multiple 4-GB zipfiles, which can be spanned across multiple DVD-Rs as a backup set. The zipfiles are limited to 4 GB because that's the maximum for standard zip file format.

If, after you install ZipBackup, the desktop icon doesn't show up in your screen, do a Create Shortcut for C:> Program Files > Datahjaelp > Zip Backup to CD. Then move the .lnk file to C: > Windows > Desktop

While ZipBackup supports differential and incremental backup for use with DVD-RW, I don't recommend using it. Instead, simply burn a complete image to DVD-R.

How to set up a DVD-R system

You will need about half the space your hard-drive files currently occupy free to allow storage of the backup zipfiles on your hard drive to store the backup zipfiles before converting them to DVD images. Add to that 4.5 GB to allow for creation of an .iso DVD-format image file to contain these zipfiles, which is what will actually be burned to DVD. Even more free space is better.

I got my 13.5 GB of files onto two DVDs. I still had plenty of room for an uncompressed backup copy of Windows and a copy of ZipBackup outside the main backup zipfiles. This allows separate installation of the OS and backup program before starting restore.

The Windows directory contains an installable copy of Windows. Creating a Windows OS backup archive is legal for the licensed user. Startup contains a copy of the boot floppy, which is useful even if booting direct from DVD -- for example, if a hard disk has to be partitioned and formatted before a restore. Create a reg_key.txt file, then put copies of all the registration keys needed to install the OS and backup program and anything else that needs identifying before restoring files. Place the file in the startup disk folder.

While DVD jewel-box inserts are also a good place to record registration IDs, putting them in a file is a good way to make sure that they are available in legible form when they are really needed.

The folders are added to the DVDs along with the zipfiles. You should put startup on all the backups. This will save time during a restore.

The DVD_cache directory shown above DVD_temp is where the DVD isos will be stored temporarily before burning. I specified them to give them fixed locations for subsequent stages of setup. You are not obligated to use my directory names, but these are the directory names which will be referred to later in the article.

How to set up ZipBackup

The first thing to do is open Backup > Files to Backup, as shown below. Then click Include folder information.

Next, enable the following:

• Include Registry.
• Include system state. NT4/2000/XP/2003 users, read the help-file entry.
• Include Drive Info As Folder. This puts the path names with each file to allow it to be unzipped back to its original location.
• Optimize used space. This puts big files on the first zipfile.
• Verify Zip file after backup. The time to find out that something is wrong with a backup is before you burn it to DVD-R.
• XP compatible filenames. XP/2003 users only.

You might want to enable: Use Password - extra security. It uses zip encryption on the backup zipfiles. Use this feature only if making the data unavailable to the wrong people is more important to you than being able to recover the data yourself.

If a menu entry doesn't stay checked, check the backup/exclude windows below to make sure it was entered properly, as shown below.

The exclusion files/folders are on the right. Add files/folders by going to the Files to Exclude item in the Backup menu. Then browse to Add Folders or Add Files. Or enter an explicit path manually via Add.

Exclude cache/temp files and the swap file from backup as shown. The Windows 98SE swap is WIN386.SWP, and the Windows 2000/XP/2003 paging file is called pagefile.sys. The OS will recreate the swap file when it is installed. To add the swap file, first find the swapfile path. Then use File > Exclude > Add > to manually enter the swapfile path.

Exclude only files you are certain don't need to be saved. Err on the side of caution.

When setup is complete, it should look something like this:

Save the backup job: File > Save Backup Job. Close all open applications, including the ones in the System Tray, to reduce the number of "busy" or uncopyable files. Run the backup by clicking Start. I recommend running backups overnight; if you have a significant amount of data to back up, this will take several hours.

At the bottom of the screen is the Progress Bar. Note that this is a dual bar during backup operations: The top bar shows progress of zipping a file, while the bottom shows the overall progress.

The backup took about 5.5 hours. The "Warning, some files were skipped" message was shown, but it's nothing to panic about. Simply check the detailed log. It will probably show that they were in use by Windows when you were running the backup or that they're scratch files you don't want anyway. If the missing files are important, reopen the zipfiles as indicated by the log in Winzip or equivalent, then reinsert by hand with folder information enabled.

How to burn backup files to DVD-R

In the following example, the Nero Express CD/DVD burning program is used. The zipfiles need to be turned into iso image CD/DVD format files burnable to DVDs, as shown below:

You're burning bootable data disk(s). Bootable data disk means that the user can boot directly from CD/DVD on computers with any motherboard BIOS that supports this. The image below shows how to configure Nero with temporary ISO files, which are what is directly burned to the DVD-R. While it's not strictly necessary, if one has to delete an ISO file because it didn't automatically get deleted for some reason, it's much better to know where it is in advance.

To get to the configuration screen, hit the More button, as shown below. Click the Configure button. Then click the Cache tab. Enter the DVD cache directory path.

Next, open the DVD_temp directory from Windows Explorer. Drag and drop them into the disk content window above. These will be burned to DVD-R.

Since the zipfiles are limited to 4 GB, you've got over 500 MB of free space per DVD-R to work with. Use this free space for backup software, OS, or other things you must have access to before doing a complete install. Note that a stripped-down installable OS version should work if necessary, as you are burning your original environment to DVD-R, and that is what you will recover.

Items external to the zipfiles are placed in subdirectories under DVD_temp. To do this, drag the subdirectories into the window to fill the empty space on the data-used bar as you see here. I suggest putting a copy of the startup and backup programs on all the backup disks so you won't have to look for them. Label each disk BACKUP1, BACKUP2, etc., as you are prompted to enter disk names.

How to perform a complete system restore

Restore from any DVD drive compatible with your media type, including read-only. The following assumes complete restore to a blank computer with DOS-formatted hard drive. My DVD-R is Drive F: -- yours will be depends on your specific configuration.

Print or write down the registration keys before you start the installation process. Then:

• Reinstall Windows.
• Install a copy of ZipBackup from DVD-R.
• Run ZipBackup, and open the restore screen. Eject the DVD-R with Windows. Put the first backup DVD-R in the drive. Open Restore > Open File to Restore from. Go to the DVD drive. Select the zip file, and open it. Click the Select All button. If the Add stored path to destination path checkbox isn't checked, check it. Once you select file(s) to restore, the Start button to the right of the Select all button will be activated. Click it. Once these files are restored, go either to the next zipfile on the disk or, if there isn't one, to the next disk. Do this until you have restored all the zipfile content to the hard drive.
• Reboot. If you are on a new computer, you'll probably be asked to put in whatever driver disks came with it as it picks up different hardware than originally installed. Do so. You may have to reboot after this.
• You're done.

How to troubleshoot archival zipfiles

"DVD rot" can cause corruption in a zip file. DVD rot is the common name for problems that can interfere with the ability to recover information from a DVD when stored; they include the dye that actually holds the information, or corrosion in the metallic substrate under it. This damage may be repairable well enough that you can get some or all of the affected data back. Use a tool for repairing zip file structures like Zip Repair. This reads the zipfile and rewrites whatever can be recovered to new zipfile with a user-selected filename.

One other reason why I like non-proprietary compressed archival formats like .ZIP for archival storage is that there are numerous compatible third-party tools. With a proprietary file format, you're stuck if anything goes wrong and the vendor no longer supports that format. Believe me, it happens.

Make sure your backup job file is set to store the zipfiles to your DVD_temp directory only. Do not burn to DVD. Set it to whatever fits your work style. However, this method is not suitable for daily backups, even to DVD-RW. For that, you should be using a mobile rack, RAID array, or network server. Remember that these backup files occupy a lot of space, so burn them to DVD-R so you can delete them ASAP.

A. LIZARD is an Internet consultant in the San Francisco Bay Area. He has been writing for technology magazines and Web sites since 1987.

Discuss this Recipe with more than 2,600 other registered system builders. Visit the TechBuilder Recipe Forum today.