Data security

Introduction

Most businesses are absolutely dependent on the information in their databases and records - loss of this data would probably be catastrophic for most businesses.

Also, it is well known that relying on just one copy of the information stored on the hard drive is a recipe for disaster, as data can get deleted by mistake, and hard drives do fail.

Also, if business accounts are kept on computer, they are just as vulnerable, if only one copy is kept, on the hard drive.

It is therefore essential to set up a system in which back-ups of all data are made on a regular basis, and kept in a secure environment.

This requires the data to be stored on a removable medium, such as high capacity disks, tape, or tape cassettes.

The process of backing up data can be done in two ways :-

Method 1

On day 1, the whole data is backed up to removable disk or tape.

On day 2, the data that has been changed on that day is backed up to removable disk or tape.

On day 3, once again, the data that has been changed on that day is backed up to removable disk or tape.

On all subsequent days, as before, the data that has been changed on that day is backed up to removable disk or tape.

After some specific number of days, say a week, or a month, the whole data is backed up again, and the process starts again, using a fresh set of disks or tapes.

Then again, after the specific number of days, the whole data is backed up again, and the process starts again, using a fresh set of disks or tapes.

Once the process has been done three times, so that there are three sets of disks or tapes, the first set of disks or tapes, containing the oldest data, can be recycled., and so on, through all the three sets of disk or tapes.

Note that a set contains one disk or tape with the whole data on it, and several disks or tapes with daily updates on them.

Method 2

On day 1, the whole data is backed up to removable disk or tape.

On day 2, the whole data is backed up to a fresh removable disk or tape.

On day 3, the whole data is backed up to another fresh removable disk or tape.

On day 4, the whole data is backed up to disk or tape, re-using disk or tape 1.

On day 5, the whole data is backed up to disk or tape, re-using disk or tape 2.

etc.

Storage of media

Both of the above systems will result in a copy of the data which is one day old, plus other copies of the data which is older.

This process of keeping generations of data is sometimes known as Grandfather / Father / Son, where Son is the most recent data, and Grandfather is the oldest data. It is always the Grandfather disk or tape, or set of disks or tapes that is re-used.

It is vital to consider how these disks or tapes are to be kept.

The disks or tapes must be given the same level of protection that would be given to other valuable business documents - ie, protection against theft, fire, flooding, vermin, unauthorised access - the minimum protection would be a lock-fast, steel cabinet. It may be more appropriate to use a safe.

© 1998 Ron Turner

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