Backup: Definition, Explanation & Examples

Definition and basic principle of a backup

A backup describes the targeted protection of data by creating a copy that can be used for recovery in the event of unexpected data loss. In professional data security concepts - both in the private sphere and in companies - backups form an essential basis. Copies of files, system configurations or entire IT environments are stored on external data carriers, network storage or, increasingly, on cloud platforms. A backup enables recovery after disruptions such as hardware defects, malware attacks or accidental deletion.

Functionality and backup strategies

Depending on requirements, various methods are available for backing up data. The focus is on full backups, incremental and differential backups. With a full backup, all selected data sets are backed up completely - a procedure that offers maximum recovery convenience in an emergency, but at the same time places high demands on storage and runtime. Incremental backups only cover the data that has changed since the last backup, which significantly reduces storage requirements and backup times. Differential backups, on the other hand, cover all changes since the last full backup, which simplifies restoring and is a middle ground between storage requirements and restoration effort. The selection of a suitable strategy depends, among other things, on the volume of data, available resources and operational requirements in terms of recovery time.

In everyday life, organisations often use a combination of these methods. A typical example is a medium-sized company that creates a full backup of its accounting data on Fridays and uses incremental backups on the other working days. If a system is lost on Thursday, all data can be reliably reconstructed by combining the last full backup and all incremental backups.

Areas of application and typical scenarios

Backups are indispensable in almost all areas of IT. Private individuals use them to protect personal documents or photos on laptops and smartphones from unintentional loss - for example in the event of theft or hardware failure. Companies use backups to protect business-critical information, customer data and complex IT infrastructures. In regulated sectors such as healthcare or the financial sector, there are even mandatory requirements for regular backups, for example to fulfil data protection and compliance requirements.

Practical experience shows how complex backup concepts can be. An IT department of a large online provider looks after numerous servers with sensitive customer data and operational systems. Close-meshed daily backups are made to the data centre, supplemented by additional offline backups on external data carriers. In this way, recovery is guaranteed even in the event of malware attacks, server failures or accidental deletions.

Recommendations for implementation

For an effective backup strategy, we recommend following the tried and tested 3-2-1 rule: there should be three copies of each important file, spread across at least two different storage media; one of these copies should be stored at an external location or in the cloud. It also makes sense to regularly check whether the backed-up data can be restored by means of targeted restore testing. This is the only way to ensure that backups can actually be used in an emergency. Automated processes and monitoring also help to keep the current status of the data backup transparent and to recognise weak points at an early stage.

Private users, for example, benefit if family photos are stored locally, on an external hard drive and also in a trustworthy cloud service. Companies, on the other hand, should adapt both the backup intervals and the encryption specifically to the respective data types. This ensures that sensitive information is protected and legal requirements are met.

Advantages, challenges and current developments

Sophisticated backup solutions enable reliable recovery after various loss scenarios and make a significant contribution to quickly restoring business capability after incidents. The introduction and maintenance of such systems requires organisational care, particularly when it comes to the secure storage of data, the detection of recovery problems and compliance with regulatory requirements. What's more, encrypted and very large data sets in particular can delay or complicate recovery.

Automated and cloud-based backup systems that also integrate protection mechanisms against ransomware and targeted cyber attacks are becoming increasingly popular on the market. Modern applications analyse backup processes in real time, detect deviations at an early stage and thus increase reliability. This means that the backup strategy is constantly evolving and remains a central component of any IT security architecture that needs to respond reliably to changing threat situations.