Sunday, January 14, 2007

Data Backup-Recovery and CYA

Has it happened to you yet?

Floppy disk with important data went bad?

CD or DVD with your favorite pictures got scratched?

Hard drive crashed without any, warning PC won't boot up?

Unless you have personally experienced the loss of data, whether it is pictures, important documents, spreadsheets, databases, music files, graphics or software, you will never understand why it is so critical to do backups on a regular basis to protect yourself.

Simply put, Backing-up is the activity of copying your files or databases so that they will be saved in the event of an equipment failure or other catastrophe. Backing-up is usually a routine that is part of the daily operation of large businesses using mainframes as well as by the management of smaller business computers. For home personal computer users, backing-up is also necessary but usually neglected.

The retrieval of the files you backed up is referred to as restoring them.

In the field of information technology or data processing, backup refers to the copying of data, so in the event they are needed, these additional copies may be restored after some type of a data loss.

Backups are normally used for two purposes:

1. In the event of some type of disaster, they are used to restore a computer to an operational state following the disaster.

2. In case files have been accidentally deleted or corrupted, you can restore small numbers of files.

What are the types of backups?

1. Full backup

A backup of all (selected) files on the system. This type of backup is essentially a waste of time, for the simple reason that in order to restore files, the operating system must be intact and bootable.

2. Incremental backup

A backup that only contains the files that have changed since the most recent backup (either full or incremental).

The advantage of this is quicker backup times, as only changed files need to be saved.

The disadvantage is longer recovery times, as the latest full backup, and all incremental backups up to the date of the data loss need to be restored in the appropriate order.

3. Differential backup

A cumulative backup of all changes made since the last full backup.

The advantage to this is the quicker recovery time, requiring only a full backup and the latest differential backup to restore the system.

The disadvantage is that for each day elapsed since the last full backup, more data needs to be backed up, especially if a majority of the data has been changed.

No one can ever predict if and when his or her hard drive will crash or when a floppy disk or cd will malfunction. It is no fun when it happens and you find out you has lost data of some type. Determine what you have on your computer that is extremely important to you and set up a plan to back those files up on a regular basis. Very small files can be copied to a floppy disk; large files can be copied to a CD or DVD. Keep a log of what you backup and when, so if you have to recover or restore a file or files, you will be able to easily find what you need.

There numerous software programs available to backup/restore files. Most of them allow you to compress the data that is to be backed and this simply conserves space on the backup medium. For large numbers of files or very large files, this is a good way to go. If you only have a few files and they are small, there is really no reason to compress them. Keep in mind that if you compress the files during backup, you will need the same software to decompress the files if they have to be restored.

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