Development and Managed Hosting
ANEXIA
APR
21
2021

The 3 best backup strategies for your data backup

Written on April 21, 2021 by Michael Hiess

An overview of the different backup strategies: full backup, incremental backup and differential backup

It always happens at the worst possible time. Suddenly important data has disappeared. Nobody wants to experience a data loss and yet, it happens that the question of a backup only arises when problems occur.

In case of an emergency, the best system is only worth as much as its backup. If a serious and permanent system failure or data loss occurs for unexpected reasons, then good advice is dearly needed. It is also helpful to have a copy of your data in case of accidental deletion, data theft or cyber-attacks. Without a backup, all data can be irretrievably lost in the worst case.

That’s why it’s important to think about it in time and implement a functioning backup and recovery strategy to be prepared for emergencies.

An up-to-date backup is a kind of life insurance to survive any conceivable disaster scenario by restoring the affected system through a functioning backup recovery.

Backup Strategie - Wiederherstellung

Those data and changes that occurred between the most recent backup and the failure are lost forever with all backup methods. Therefore, it is important to choose a backup strategy that minimizes data loss within the limits of technical possibilities and available storage space.

Basically, there are three different backup strategies, each with different advantages and disadvantages.

backup strategy - full backup

The full backup or the complete backup

As the name reveals, this is a full backup of the system.
The advantage of a full backup is the simple handling. In case of a restore, the last full backup is simply imported. The disadvantage of this method is the time needed for such a full backup. As a result, the time interval between the individual backups is much bigger than with all other methods and therefore the amount of data in the event of a data loss is also the highest.

backup strategy - incremental backup

The incremental backup or the sequential backup

The incremental backup requires a full backup. With an incremental backup, only the data that has been added or changed since the last full backup, or the last incremental backup is backed up.

The advantage of this method is that, compared to a full backup, incremental backups require little storage space and can be created very fast. Due to this fact, it is possible to back up the increments in short time intervals. In case of data loss, the amount of data is the smallest with this strategy.

When the backup is restored, the full backup and each individual incremental backup are imported one after the other to recover the system completely. For this reason, the  required time for restoring is significantly higher than for all other strategies. This is also the main disadvantage of this method. With this strategy, it is important to find a good balance between the number of incremental backups and the recovery time required to adjust the backup cycle accordingly.

backup strategy - differential backup

The differential backup or the backup of differences

Differential backup also requires a full backup. In a differential backup, only the data that has been added or changed since the last full backup is backed up.
During the restore period, only the full backup and the last differential backup are restored. All backups in between can be ignored or deleted. The differential backup grows steadily with the number of data changes and can theoretically exceed the size of the full backup, but this does not make sense.

This method offers the possibility to well balance the time needed for the backups and for the recovery. Once the differential backups become too large, the backup cycle should be renewed with a full backup to continue to take advantage of this strategy.

Summary of the backup strategies

With all three backup strategies, it is important to keep track of the growth of the individual backups in order to renew the backup cycle at the appropriate time.

Ideally, there is a very small data difference between backup period and a point of failure that hopefully never occurs.

The size of data lost depends on the chosen backup strategy and is always a compromise between the backup cycle, the technical capabilities of the backup software and the actual conditions of the backup systems.

Further information

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