By Stephen Bucaro
It is important to create a backup procedure for your network. The backup procedure
should define a schedule and the type of backups that will be created. Each backup
disc or tape should be clearly labeled and recorded in a log.
Data files need to be backed up more frequently than programs. Usually only servers
are backed up. Data stored on workstations is frequently neglected. Users should be
instructed to store important data in a shared folder on a server.
The simplest backup is to copy selected files to a backup storage media. A copy
does not set the files archive attribute. If you have put several hours of hard work
into an important project, you can protect your investment by immediately creating a copy.
For a regular backup plan there are three types of backups:
Full backup. This backs up all files regardless of whether they have changed or not.
The archive attribute is set for each file.
Incremental backup. This backs up only files that have changed since the last full
or incremental backup. The archive attribute is set for each file that is backed up.
Differential backup. This backs up only files that have changed since the last full
or incremental backup. However the archive attribute is not set.
A small amount of data may be backed up to floppy diskettes. Write-able compact disks
(CD-W) are becoming more popular as a backup media for home and small business users.
A CD-W can store up to 650 MB of data.
The most popular backup media is magnetic tape. There are three common types of magnetic tape:
Digital Audio Tape (DAT) comes in storage capacities from 1 to 12 GB.
Digital Linear tape (DLT) comes in storage capacities from 10 to 35 GB.
Quarter-Inch Cartridge (QIC) comes in storage capacities from 40MB to 25 GB.
After recording, you should store your backup media in a safe place. The best
storage place is a secure fireproof vault. The backup storage vault should not be
near the network equipment room. You don't want a fire in your equipment room to
destroy the data on your servers and your backup tapes too. Depending upon the amount
of data on your network, you may want to store full backups or even incremental backups
in a secure locker at another site.