Backing Up Files in NT

Mention the word backup to a typical computer user, and you'll probably hear something like, "I never do it." The concept of backing up files is often disregarded and poorly understood in computer circles. Unfortunately, the consequences of not properly backing up your files can put you out of business.

Starting with this article, the Windows NT Magazine Lab digs into the topic of backing up files in Windows NT. Over the coming months, the Lab will review various backup applications for NT. Last year, few NT backup applications existed. Today, vendors provide numerous NT backup programs for everything from protecting the data files on your workstation to enterprise Hierarchical Storage Management (HSM).

This month, I'll concentrate on the importance of backing up your files correctly. I'll also look at backup solutions and hardware considerations for different network environments.

The Importance of Backups
Backing up your files is pointless unless you establish and follow a backup strategy and take all the necessary precautions. Let me give you a real-world example. I consulted for a small company (about 15 employees) that performed daily tape backups of its server and copied critical files to notebook computers using batch files. The company established a procedure to back up the latest files from the server and take the backup tapes off site every Friday. However, the company became lazy and did not take any tapes or the notebooks off site. Instead, the company left the backup files on site. This approach seemed relatively foolproof. After all, the employees were performing backups in a way that provided redundancy in case something happened to the master files.

Despite taking these precautions, the company suffered a catastrophic loss when a fire burned down the building. A firefighter saved the server 20 minutes before the fire would have destroyed it--the backup tapes and notebooks were useless because they burned in the fire. Fortunately, I was able to recover the files from the damaged server, and the network was up and running the next day.

So what's the moral of the story? Although the company was backing up its files, it wasn't taking all the necessary precautions.

Although seemingly insignificant, this example points out some misconceptions about performing backups. First, never assume that your company is following its prescribed backup policy. Compliance is an important part of backup. You need to establish the optimal strategy for your backups and then stick to it. The company in the example was following its backup strategy but didn't move the tapes and notebooks off site. Considering that roughly 80 percent of all businesses that lose their database go out of business, this company was very lucky.

Second, don't be ashamed to copy files to a hard disk (i.e., using notebooks to maintain copies of data)--tapes are not the only medium that works. Finally, don't assume that just because you've backed up your files, your data is safe. Store your backups off site.

Likewise, don't rely on fault-tolerant systems as your backup systems. As the name suggests, fault tolerance lets systems continue to function when something goes wrong. When all fault tolerance fails, you use your backup tape to restore the system and data. Backups are the last ditch effort to save data and systems.

But suppose the tape is no good? A common problem with backup procedures is the failure to verify tapes. If you expect the data on a tape to be good for five years, you are probably in for a surprise. (An employee at Digital Equipment lost years of email as a result of a bad tape header. Although specialized companies can now recover such data for you, the cost is high.) How can you tell if the data on the tapes is OK? Simply restore the tape and have as much redundancy as you deem appropriate (i.e., if necessary, have more than one tape with the same information). All these steps (performing backups on a regular basis, storing your backups off site, and verifying the quality of the data on the backup tapes) are essential to a sound backup strategy.

The Point of the Exercise
Backups not only let you circumvent computer disaster, but you can use them with fault tolerance to rebuild a crashed server; frankly, backups can save your job. The list of reasons why you need to back up your data includes

• Catastrophic losses: Natural disasters, such as the fire I described previously, can happen.
• User-induced errors: Users can accidentally delete files or lose code because of an improper command.
• Hardware failures: Hard disks can fail, and power supplies can short out.
• Vandalism and security failures: Hackers can destroy or alter files.
• Software failures: Entire databases can become corrupt.
• Audits: You need to produce archived data for legal purposes.

You need to take all backups seriously. File backups can be a source for serious legal repercussions and can be subpoenaed in court with due cause. Be careful about what you back up.

Successful backup strategies must be set as policy at the company level. Nothing is more frustrating than establishing a backup strategy without company support--without it, you will probably have a hard time accomplishing your objective, and you may not receive adequate funding for proper backups.