Full vs. Incremental vs. Differential Backups: Comparing Backup Types

This blog was originally published in January 2012 and was updated in June 2023.

In today’s data-driven world, the protection and reliability of our valuable information is vital. The potential impact of data loss or corruption on individuals and organizations cannot be understated. Therefore, establishing a strong backup strategy is essential to ensure data security and minimize potential disruptions.

When it comes to backups, there are multiple types available, each with its own advantages and limitations. In this blog post, we will explore the realm of backups and conduct a comparative analysis of three backup types: Full, incremental, and differential backups.

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What is a full backup?

A full backup is a comprehensive data backup strategy that involves creating a complete, exact copy of all data and files in a database. Depending on an organization’s specific requirements, legal or otherwise, full backups are typically performed periodically, such as daily, weekly, or monthly.

Full backups are most suitable for critical systems or sensitive data that cannot afford any loss or downtime, allowing for a complete recovery of data in the event of data corruption, hacking, system failures, or natural disasters. In addition, they are used for restoring or moving data to a new system.

Full backups also provide a baseline for subsequent incremental or differential backups, which we will discuss a little later.

In order to implement effective full backups of your database, you must follow some best practices. This includes establishing a regular backup schedule, regular testing to ensure data integrity, storing backups securely and offsite/in multiple locations, and documenting backup procedures.

Advantages of full backups

Full backups provide several benefits in terms of safeguarding data and facilitating recovery processes, as they encompass thorough data replication and enable complete system restoration during critical situations.

• Comprehensive Data Protection: A big advantage of full backups is that they capture every bit of information, including the operating system, applications, databases, and user files, ensuring that all critical data is replicated and protected against loss or corruption. In the event of system failures or catastrophic events, the ability to restore the entire system from a full backup ensures minimal data loss.
• Simplicity and Ease of Restoration: Since full backups capture a complete copy of all data and files, it simplifies the recovery and restoration of a database. This allows for faster and more convenient restoration, minimizing downtime and allowing organizations to resume normal operations quickly.
• Independent Backup Copies: The self-contained nature of full backups — capturing a complete copy of all data and files — allows each backup set to be accessed and restored independently. This provides flexibility in data recovery and allows organizations to retrieve specific versions or data sets as needed effectively.
• Fast Recovery: Restoring a system from a full backup is generally faster when compared to other backup types, allowing for minimal downtime and fast resumption of operations.

Disadvantages of full backups

While full backups offer numerous advantages, it is important to consider their potential disadvantages in order to make informed decisions regarding backup strategies.

• Increased Storage Requirements: One of the disadvantages of full backups is the increased storage requirements due to the fact that they capture a complete copy of all data and files. As the amount of data grows, organizations may need to allocate additional storage resources to accommodate the larger backup sets, leading to higher costs.
• Longer Backup Time: Full backups have longer backup times due to the comprehensive nature of capturing all data and files, which can be particularly time-consuming when dealing with large datasets.
• Network Bandwidth Utilization: This is another potential disadvantage when it comes to full backups. Since they capture all of the data and files, they require significant network resources to transfer backup sets over the network, resulting in increased network congestion and potential performance issues.
• Frequent Backup Cycles: An aspect to consider with full backups is the frequency of necessary backup cycles. Full backups can be resource-intensive and time-consuming, and organizations may need to allocate more time and storage resources to accommodate regular full backups.

Learn how to restore a single InnoDB table from a full backup after accidentally dropping it in this blog.

What is an incremental backup?

Incremental backups capture and store only any changes made to the data since the last backup (full or incremental). This results in smaller backup sets, reducing storage requirements, time to take the backup, and network usage, as compared to full backups. These backups are particularly suitable for those environments where data changes frequently.

To implement incremental backups effectively, it is important to establish a baseline with a full backup that serves as the initial reference for subsequent incremental backups. And in order to ensure data integrity and recoverability, DBAs should be testing incremental backups regularly, including the verification of the integrity of backup sets, as well as doing test restores.

When deciding where to store incremental backups, consideration should be given to offsite storage in order to provide protection against data loss or damage, and the regular scheduling of incremental backups is essential to ensure that all data changes are captured and maintain a reliable backup chain.

Advantages of incremental backups

In this section, we will explore the benefits and advantages of utilizing incremental backups for data protection which makes them a valuable database backup solution.

• Reduced Backup Time: This is a big advantage of incremental backups. Since only the changes made since the last backup are captured, the backup process is far faster as compared to full backups.
• Lower Storage Requirements: Incremental backups help lower storage needs by only storing the changes made to data since the last backup rather than saving the entire dataset. This optimizes storage space and allows for more frequent backups.
• Faster Recovery: Faster data recovery is a key advantage of incremental backups. Because this process allows for selective restores of only specific changes since the last backup, it reduces the time organizations need for data recovery.
• Bandwidth Optimization: Because a smaller amount of data needs to be transferred during an incremental backup, it can reduce network resources and congestion. For issues that may arise during peak network usage, this can prove to be valuable in keeping applications performing efficiently.

Disadvantages of incremental backups

Although incremental backups do provide several advantages over other backup strategies, it is essential to be aware of their potential drawbacks to make well-informed decisions that work for your requirements.

• Longer Restore Time: The restore process for incremental backups may take longer because it could involve having to sequentially apply multiple incremental backups to restore any missing or corrupted data that spans several backup versions.
• Increased Complexity: Implementing incremental backups can introduce increased complexity compared to other backup strategies, as DBAs always need to manage and maintain the backup chain. This requires careful tracking and organization to ensure data integrity and availability at all times.
• Dependency on Full Backup: The restoration of data from an incremental backup strategy still relies on the availability of an initial full backup, as well as all subsequent incremental backups.
• Longer Backup Chain: Incremental backups create a longer backup chain as each backup captures the changes since the last backup, including all incremental backups. Because each of these backup sets must be managed and stored, the length of the backup chain grows over time, requiring adequate storage capacity that may increase costs.

Want to learn more about incremental backups in MySQL using page tracking? Check out this blog!

What is a differential backup?

A differential backup backs up and keeps all the changes made since the last full backup was taken. Unlike the incremental backups discussed above, which capture only the changes made since the last backup, differential backups result in larger backup sets over time.

Differential backups are ideal when organizations must find a balance between backup size and restoration time. This strategy is optimal for quick data recovery, as the process involves applying the latest full backup followed by the most recent differential backup. It also simplifies data restoration compared to incremental backups, which require multiple backup sets to be used.

In order to optimally use differential backups, it’s vital to establish a regular backup schedule, test and verify data integrity constantly, store all backups securely and maintain up-to-date documentation of backup procedures.

Advantages of differential backups

Differential backups provide significant benefits in terms of restore efficiency and storage space optimization, making them a valuable choice for organizations looking for a backup strategy.

• Efficient Restore Process: Differential backups offer an efficient restore process by requiring only the latest full backup and the most recent differential backup to restore the data. This results in a quicker data restoration than incremental backups, which involve multiple backup files or sets.
• Storage Space Optimization: Differential backups optimize storage space usage by capturing and storing only the changes made since the last full backup, eliminating the need for multiple backup files to restore data. With one differential backup containing all changes since the full backup, storage requirements are reduced while still ensuring efficient data recovery.
• Simplified Data Recovery: The data recovery process for differential backups is simplified and streamlined as it requires only the latest full and differential backup, making it more efficient than incremental backups.
• Faster Backup Times: Unlike incremental backups, which require scanning and comparing the entire backup chain, differential backups involve capturing the cumulative changes in a single backup operation, minimizing backup time and resource utilization.

Disadvantages of differential backups

In this section, we examine the potential disadvantages and drawbacks of utilizing differential backups for data protection.

• Increasing Backup Size Over Time: One drawback of differential backups is they often increase in size over time. Since each differential backup captures all changes made since the last full backup, the backup files gradually become larger than incremental backups.
• Longer Restore Times: Differential backups can lead to longer restore times compared to incremental backups because when restoring data involves applying the latest full backup and all subsequent differential backups.
• Higher Storage Requirements: Due to the accumulation of changes since the last full backup, differential backups can require higher storage requirements because of larger backup files over time.
• Potential Data Redundancy: Differential backups may result in data redundancy, as each subsequent backup includes all changes since the last full backup, leading to the possibility of the same data being backed up several times.

Choosing between incremental vs. differential backups

When trying to choose between incremental and differential backups, you will need to understand what you are trying to accomplish with your backup strategy and consider factors such as the size of your data, how long backups will take, the efficiency of your restore process, the storage requirements for your data and data sets, and the potential for downtime to restore said data.

One backup strategy may be better when trying to minimize data size, and another may be better when your focus has to be on the ease and quickness of data recovery. With that in mind, let’s take a look at a few factors that should help you decide what strategy would work best for your needs and requirements.

Performance Considerations:

When considering the performance abilities of these two backup strategies, incremental backups are generally faster — but the restoration process can be slower, as previously discussed. Alternatively, differential backups generally take longer, but data restores are often faster. Consider which is more important to match your specific needs.

Storage Requirements:

When evaluating the storage needs of incremental vs. differential backups, keep these factors in mind. Incremental backups generally have reduced storage requirements since only the changes since the last backup are captured. Differential backups, on the other hand, grow in size as each backup captures all changes since the last full backup. Storage costs can rise quickly, so be sure to consider your options when making your choice.

Recovery Time:

Incremental backups tend to need more time to restore than differential backups, as they require sequentially applying multiple backup files to restore the data. Differential backups, in contrast, make for faster restores as they only require the latest full backup and differential backup for the restore.

Choosing the right backup type for your needs

Having the proper backup strategy in place for your organization is vital to minimize the potential business disruption of data loss, security breaches, or corruption. And with multiple types of backups available — full, incremental, and differential — it’s important to know how they work, their advantages and disadvantages, and their use cases.

And depending on how much data you need to back up, the storage requirements for that data, how long the data takes to back up, as well as the restore efficiency of each method, it’s important to choose the appropriate strategy for your specific needs.

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