Terminology to describe the process of copying data to a safe place
This data can then be reinstated (added to the information system) if a problem occurs with the system.
The aim of creating backups is to prevent data loss in the unfortunate event that the original data is damaged or lost.
Such damage mot often results from hard disk failure; it is in fact inevitable that all hard disks will eventually fail.
Other reasons for data loss or damage includes:
software faults
theft
fire
viruses
intentional malicious damage
insufficient or inappropriate validation that accepts unreasonable data
even intentional changes that were found out later to be incorrect.
For Backup copies to most effectively guard against such occurrences, regular backups are required and then backup copies should be kept in safety; in a fireproof safe or in a separate physical location.
Types of Backups
Two type of backups that are commonly used:
full backups
includes all files - regardless on whether it has been modified or not.
partial backups
includes only those files that have been created or altered
To determine a file has changed, most operating systems have an "archive bit" which is turned on when changed.
Alternatively, using a Modified Timestamp to determine if changes have occurred since the last backup.
Frequency of Backups
depends on how critical the data is to the organisation and how frequently the data changes.
Usually Full Backups are done at least once a Week and partial backups being made daily.
A further safeguard against data loss is to rotate the media used for backups; commonly three sets are used. So if one set is corrupted, then previous sets can be used for recovery.
Backup Routines: Grandfather, father, son method
Backing up routines should use a method such as the 'grandfather, father, son' method.
The daily or 'son' backups are saved each night for a week until there are seven 'sons'. At the end of the week, the oldest 'son' will be put aside and known as a 'father'.
Each week for a period of a month a new 'father' is created.
At the end of a month when there are four 'fathers' one will graduate to 'grandfather'.
12 grandfather backups will be stored each year.
Types of Backups - quick version!
Grandfather, Father, Son (GFS) vs. Progressive (Incremental Forever) Backup Paradigm
Online/Cloud Backup
Cloud backup, also known as online backup, is a strategy for backing up data that involves sending a copy of the data over a proprietary or public network to an off-site server.
The server is usually hosted by a third-party service provider, which charges the backup customer a fee based on capacity, bandwidth or number of users.
In the enterprise, the off-site server might be owned by the company, but the chargeback method would be similar.
Implementing cloud data backup can help bolster an organization's data protection strategy without increasing the workload on information technology staff.
