Backup Strategies

by Ing. Roberto Grassi

GRSoftware President

Introduction

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. Strategies are frequently are based on a combination of these considerations and should develop a plan that lets you restore files easily should it become necessary.

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.

Change

How often your files change is another key element to consider when planning an effective strategy. For example, losing even part of one day's input at a mail-order house would result in many lost orders and lost revenues. Your strategy might be to backup only changed files periodically throughout the day to ensure that a recent copy of all files exists.

Media capacity and device performance

You should back up 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 upon the kind of backup device you use, just as you may choose a device in response to the kind of strategy you consider necessary.

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 to physically transport your media. You must also choose a device with media compatible with other devices and with the environments to which you send the data.

Media

Use only high-quality media for your backups. GRBackPro is careful to check that each media is reliable but you can increase your long term reliability of the backup when you use high-quality media.

Hardware

Unsure that your hardware is fully operational? A backup program cannot operate effectively if the drive is not perfectly working. Faulty disk controllers and other circuitry can also cause information to be written incorrectly to the media, thus compromising existing files.

Labeling

Clearly label all backup media. This will allows you to easily retrieve them when you have lost a file.

Media Rotation

There are two types of backups:

Full
Modified (also known as incremental or differential)

A Full backup of your files requires mode time and media. A full backup however, should be performed regularly (at least once a week, depending on your work volume).
A modified backup saves time and media. Usually, only a few files on your hard disk are new or have been changed since 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.

Basis 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 business was struck by fire, flood, or theft, you can ensure that your system can be restored by keeping a recent copy of your files off-site.

Secure On-site storage Store your media in a fireproof safe to enhance security. Remember that you want to have easy access to your most vital backed-up files.

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

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

Backup Strategy.

To minimize data loss and computer downtime when a hard disk crash occurs, you should follow these rules when backing up your data:

Perform a Full backup of your hard disk, and make sure that the option "Clear archive attribute bit on the source file" on the Backup dialog is checked. Place this backup in a safe place.
Perform Modified backups as a part of your future backup strategy rather than backing up your entire system. This method saves time and media. When you select the Differential mode the backup program backs up only those files that have been modified or created since the last Full backup.
Maintain at least two sets of backups with Modified backups, and rotate these sets to be prepared for a system crash. Restoring the latest backup set updates your system to its latest stable state.

Strategy Implementation

You should consider how often you want to backup your files and which files you should back up. A regular Full Backup and Restore verification is recommended but whether you supplement that with Incremental or Differential backups depends on your needs.

These questions may help clarify your situation:
If your files are damaged or deleted, how many days of work does it takes to re-create them ?
What is the oldest version of a file that you anticipate you may ever need ?

Rotate a minimum of three sets of media so that you always have a recent Full backup and two alternating sets of media which contain specified backed-up files. If either of these sets becomes damaged, you have another recent copy on hand.