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A firewall won't protect your data from a real fire.

What would be the cost of data (accounts, documents, family photos) on your computers being unavailable for one or two days or one or two weeks -- or if the data were gone forever? What would be the cost of re-inputting the company's data and reentering its documents? What would be the impact of losing the only copy of family baby pictures?

What you should back up and what you need to back up depends on your individual needs, your business needs, how hard it would be to recreate and reenter the data and possibly other factors like customer service and legal concerns.

Backups are essential in case the hard drive in your computer malfunctions, your computer is stolen, the desk your computer sits on is over-turned, a virus clears your computer's hard drive or the building your computer is in is destroyed by fire, flood, tornado or earthquake.

A backup from one computer to another in the same building, or to an external hard drive, will protect data against a disk drive malfunction or accidental file deletion, and it will do it in a way where the data can be very quickly searched and restored. However, such backups don't protect data from being destroyed if a virus gets in the network, or if there is a large voltage surge, the building burns down or there is a flood or earthquake.

Off-site backups protect data from a single disaster by storing the off-site backups in a building sufficiently separated from the computer and the on-site backups that it is not susceptible to damage by the same disaster.


1. You don't necessarily have to back up your entire computer, but you should backup critical, hard-to-replace data.

This might include:
- Address books
- E-mail
- Calendars and schedules
- Documents
- Project work and project data
- Databases
- Freeware installation programs that are no longer available
- Web browser favorites
- Digital photos
- Settings
- Saved games
- Data on diskettes, CDs and DVDs (you may want off-site backup copies)


2. As well as backups of data from your system, you should have backup copies of the disks and CDs you need to re-install your system on a new computer. Don't forget copies of irreplacable printed material, like special instructions and notes.

Write the license or registration numbers of your software in on-site and off-site notebooks, or use a fine soft-tip pen to write them on the product and backup CDs.

Belarc Advisor (free download here) will create an HTML file with an inventory of the programs on your system and their registration numbers. This file can be copied with the backups and also printed off.


3. At least one copy of your backups should be stored on-site and at least one copy of your backups should be stored off-site at all times.

The on-site copies facilitate rapid restoration in the event of accidental deletions.

The off-site copies facilitate recovery from disasters.

The off-site copies should be stored where they won't be subject to the same fire or flood damage as the on-site copy.

As a minimum for a home, you might use a son-father-grandfather system. Using this you always have at least one copy of the backup on-site, one copy off-site and the third copy is in transit or at either location.

Depending on individual circumstances, quite a few generations of backups may be necessary to meet business and legal needs.


4. Depending on needs, one might do daily incremental backups and weekly full backups.

A full backup is a backup of everything. An incremental backup is a backup of only those things that are new or have changed since the last backup.


5. The duration that you keep (retain) long-term backups may be dictated by legal or accounting guidelines. If you are a business or institution, it is best to check with both your accountant and your lawyer.

A common practice for mid-sized and large companies is to do daily backups that are retained for 1-2 weeks, weekly backups that are retained for a month, and monthly backups that are retained for 16 months (longer than a year in case year-end balancing problems turn up late).

Frequent short-term backups primarily protect against accidental corruption and deletion.

Long-term backups serve 2 purposes:
(a) in case seldom used files become corrupted and that corruption is not noticed for a long period of time,
(b) in case of legal or accounting difficulty, as an archive of short-lived files to later document discussions, transactions or work.


6. Backups can be kept on diskette, CD, DVD, tape, a second computer, external hard drive or off-site file server.

For tape backups to last longer than 12 months, the tapes have to be kept at a steady temperature and re-tensioned (run to the end and rewound) at intervals no greater than every 12 months.

A backup on an off-site fileserver should never be the only backup. There should also be an on-site backup.

A backup on another on-site computer or external hard drive should never be the only backup. There should also be an off-site backup.

Over the long term, magnetic media can be affected by the electro-magnetic fields of monitors, power supplies, speakers (shielded or not), cell phones, microwave ovens, telephones, TV, etc.

CDs, DVDs and magnetic media can be affected by being too close to heat sources, uneven temperatures, direct sunlight or extreme humidity.

Retaining data for periods longer than 16 months is beyond the scope of this document. Consult the manufacturer of the storage media you plan to use.


7. Backups of sensitive information should be secure. Backups can be encrypted, but backups should still be protected against theft and damage.

Backups for a small business might be stored in the owner's home, a relative's home, your accountant's office or a bank.

Backups for a home might be kept in the home owner's bottom drawer at work.


8. Backups can be made by these methods:

8.1 By inserting a CD or diskette into a drive, and using Windows Explorer to drag and drop files onto it

8.2 Using Start / All Programs / Accessories / System Tools / Backup

8.3 Using a .bat file such as:

rmdir /Q /S "x:\computername\foldername backup 2"
ren "x:\computername\foldername" "foldername backup 2"
mkdir "x:\computername\foldername"
echo Backup now starting
xcopy /e /h "\\network machine\share\foldername" "x:\computername\foldername"


8.3 A utility such as Norton Ghost, Acronis True Image, or Symantec LiveState Recovery

The advantage to these utilities is that you can generally back up and restore an entire hard drive without having to individually re-install any programs. They can save you considerable time in getting back up and running after an emergency.

For Mac OS, Carbon Copy Cloner

For *ix, rsync-backup

Backup software comes included with many external hard drives. But keep in mind, if the building the computer and external hard drive are in is destroyed by fire, both the original copy of the data on the computer and the backup copy on the external hard drive will be destroyed at the same time. The loss of both the original copy and backup can also happen if a hard drive-destroying virus strikes while the external hard drive is connected or if there is a lightening strike or severe power surge.


9. Periodically test that your backups are working. Make sure the backups can be restored to the type of computer you plan to use for recovery in an emergency.

With file-by-file backups of documents in a folder, a mail database and address books, this just means checking that all the files are there and that the disks haven't worn out and are still readable.

However, if you are doing full volume (disk image) type backups, as a business would probably want to do in order to be able to do a speedy restore, these backups can quietly become unusable due to major operating system or major hardware upgrades.

- If you are saving an old computer for emergency use (for restoring the backups to), ensure that the old computer is kept sufficiently upgraded with compatible hardware.

- The only way to ensure this compatibility is to test that the backups will still restore to the intended computer initially and after each hardware upgrade.

- Test by restoring your backup to a computer that has a wiped or formatted hard drive. Do not restore your data to your original computer. Restore your data to a test computer of the type that you would actually use in the event of a disaster.

- Then make sure that all the programs still work and can still update the address books, files and so on.

- If you are a small company using a consultant, watch the backup and restoration process to see that it works -- and that it works in a timely manner that meets your business needs.


10. RAID (Redundant Array of Independent Disks) may or may not enhance data security, depending on which type of RAID it is. Some types of RAID merely provide faster data access.

Those types of RAID that provide some enhanced data security only provide protection against the electrical or mechanical failure of a single disk drive. They don't protect against the failure of 2 or more disks, loss due to viruses, accidental deletion, large electrical surges, vandalism, theft or fire. RAID also doesn't guarantee protection against corruption due to RAID controller failure.

Click here for more information on RAID.

*** If you are a company that depends on computers for its continued operation, you should seek the assistance of an IT professional in evaluating your needs and seeing that they are met.


Additional info:
* Off-site backups: A critical tool for disaster recovery
* The Seven Golden Rules Of Data Backups
* The Tao of Backup
* Windows Backup for Windows XP and Windows 2000: here for your data, and here or here for your registry
* Installing Backup on Windows XP home edition
* Earlier versions of Windows Backup here or here
* Easy Backups With WinZip and Freeware
* Fred Langa: Fast, Easy Backups For Win98 / ME / NT / 2K / XP
* BBR Microsoft Application Tips and Tweaks
* BBR Windows XP FAQ
* NIST Care and Handling of CDs and DVDs
* Digital preservation: a time bomb for Digital Libraries
* Webopedia: Dictionary & Encyclopedia of Computer Terminology
* Click here to read the posts from those who helped me develop this FAQ

Feedback received on this FAQ entry:
  • The following link is giving me a 404 error. http://www.itl.nist.gov/div895/carefordisc/

    2008-07-14 15:38:50 (RWOTB See Profile)



Expand got feedback?

by keith2468 See Profile edited by JMGullett See Profile
last modified: 2007-06-20 16:24:10