Multiple approaches are best for backing up data
Backup, what backup? This is something many computer support people hear
all too often when a hard drive fails or files get erased by accident. It
is not really a question of whether your hard drive will fail, but when
will it fail. Hopefully it will be after you sell your computer. Think about
what information is on your computer and what would happen if it all disappeared.
How much critical business and personal data would you lose? But of course
it is all on your backup, right? When asked, most people seem to agree that
backing up is important. The problem is that doing backups is not always
a priority in day-to-day operation.
Backing up computer data can be done in many ways. There really is not a
"one size fits all" approach to backups. There are different needs,
resources and requirements for backup. There are different views on frequency,
on which data to preserve, and on methodology used for backups.
You must decide how much time you can afford to let pass between backups.
You will never create a system of backups that can be kept current, or restored
quickly enough to completely avoid the loss of data. You will have a dependable
backup strategy if you start by identifying critical data and considering
what would happen if the data were lost.
Is it important to keep continuous backups of everything on the server?
Generally, a lot of the files located on a computer are not critical to
your job. It is also probable that a large part of the space used on your
computer is for applications files that can be easily reinstalled.
Many people develop the habit of keeping files that are no longer necessary.
Just as with paper, unneeded data files should be discarded or copied to
an archive. Know what you have on your computer, then organize your data
so it is easy to back up and restore. Be sure that you can restore the data
files you need when necessary.
There are many types, or levels, of backup. Here are three types that cover
most of the requirements for individual users:
1) Full backup: Copy all of the files on your hard drive to whatever output
device you have chosen to use. The advantage in this type of backup is that
everything you need to fully restore your computer is available. While this
is very effective, it takes more time and uses more tape or disk space.
2) Incremental backup: Used in conjunction with a full backup process, incremental
backups are used to back up only those files that have been changed since
the last full or incremental backup. This can save a lot of time and resources
during the backup process, but it may require more time to do a full restore.
3) Partial backup: This method backs up only critical data. Partial backups
can be done as full or incremental backups.
There are many ways to back up your computer. You can back up to local devices
such as diskettes, tape, removable hard drives or a server. If you back
up to a server it is a good idea to be sure the server is also being backed
up. A few years ago backups were done to floppy disks or diskettes and later
to tapes. Today there are removable cartridge drives for easy and fast backups.
Full backups can be done to Iomega Zip drives (100MB), Syquest drives (120
MB - 230MB), or Iomega Jaz drives (1 GB). Floppies and diskettes can be
used for incremental backups. There are also Digital Audio Tape (DAT) drives
and other tape formats. The output device you choose will be determined
by the amount of data you need to back up, speed, convenience and cost.
Since backups are a long term commitment, it may be wise to pay for the
features that will make the process work for you.
Backups can be started manually or automatically. The backup of your individual
computer can be managed and controlled by you or it can be done from a server.
It is best to use the same system and process as other people use in your
department so that you can draw on the knowledge and expertise around you
if you have a problem.
Whatever backup program and process you choose, always verify that you can
recover files from your backup. Doing periodic restores of files from your
backup is a very good way to validate that your backups are working.
The best approach to data protection is a combination of several methods.
A single backup method cannot guarantee complete protection, but a careful
blend of multiple techniques will provide you with a good balance of safety
Jim Kruse is a senior computing support consultant in ITD's Computing Resource
to the November 11, 1996 contents page