Backups

The effectiveness of a good backup program depends on your approach to file backup management. The following are key considerations:

• How valuable are your files ?
• What would be the consequences of losing these files ?
• Could you replace them ? If so, what would be the time and cost required ?
• How often do these files change ?
• Do you need to keep older versions of files ?
• Does the device you use to back up files have any limitation of time, media capacity, or expense ?
• Do you need to transport or distribute your backed-up files ?
• Once backed-up, how important is immediate access to these files ?

These issues can be divided into certain basic categories: value, change, performance, media capacity, and portability.

Value

When you devise a strategy, consider your cost in time and money to replace lost files. For example, if you work for an insurance company managing client information and claims, then you would probably consider file loss disastrous. The consequence of losing irreplaceable files makes it desirable to back up your files every day to different media. Conversely, someone who uses their computer primarily for recreation may not consider the loss of files to be more than a minor inconvenience.

Change

How often your files change is another key element to consider when planning an effective strategy. Losing even part of one day's input at a mail-order house would result in many lost orders and lost revenues.

Media capacity and device performance

Ideally, you should backup completely once a day but this is not always possible due to time, media, or device restrictions. You must assess your physical setup (for example, type and size of the available backup device) to effectively plan a strategy. Your strategy depends partially upon the kind of backup device you use.

Media

Use only high-quality media for your backups. You can increase your long term reliability of the backup when you use high-quality media.

Hardware

Ensure that your hardware is fully operational. A backup program cannot operate effectively if the drive is not working properly. Faulty disk controllers and other circuitry can cause information to be written incorrectly to the media.

Labeling

Clearly label all backup media. This will allow you to easily retrieve the correct set when you need to restore data.

Media Rotation

There are two types of backups:

• Full
• Modified (also known as incremental or differential)

A Full backup of your files requires more time and media. A full backup however, is the easiest type of backup to restore from - all files are backed up.
A Modified backup saves time and media. Usually, only a relatively small number of files on your hard disk are new or have changed each week. The Incremental mode backs up any files that have changed or been created since the most recent Full or Incremental backup. The Differential mode backs up all files that have changed or been created since the most recent Full backup.

Portability

Media portability may also influence the strategy you implement. For instance, in situations where files must be circulated within your department or sent to another site, you would want to use a backup device that allowed easy physical transport of your media. You must also choose a device with media compatible with other devices and with the environments to which you send the data.

Basics of a Good Strategy

Regardless of which approach and media you choose, there are several elements fundamental to all good strategies.

Secure Off-site storage    If your files are valuable enough, consider transporting them to an off-site facility for secure storage. A business struck by fire, flood, or theft will likely need to retrieve a set of backups from an unaffected storage site. A homeowner may not need this level of security.

Secure On-site storage    Store your media in a fireproof safe to enhance security. Remember that you are preparing for a disaster, not necessarily only a computer breakdown. Small fireproof safes are very inexpensive and are appropriate for business and home use.

Write Protection    Backup copies may be the only way to recreate files in case of loss or damage. Write protecting your backup media ensures that they cannot be accidentally overwritten.

NOTE: You should write-protect used media even if it is password-protected since a password does not prevent media from being erased or overwritten.