Incremental vs. differential backup: which is better?

Backups are critical to protecting organizational data, maintaining compliance, and enabling business continuity. On paper, the best option for protecting data is a full backup, which provides comprehensive coverage of all data. This includes the copying and storing of all files, folders, and data in a secure location, ensuring nothing is left behind.

While full backups are generally ideal, this approach can consume too much time and bandwidth to rely on regularly. For this reason, MSPs and IT teams may turn to differential or incremental backup to supplement the deployment of full backups. Both incremental and differential backups are popular, feasible, and effective options to help support a comprehensive backup strategy.

Keep reading to learn more about the differences between incremental and differential backups and to determine which is best for your business needs.

Key takeaways

• Incremental backups save only the data changed since the last backup of any kind, offering faster backup times, reduced bandwidth usage, and smaller storage needs.
• Differential backups save all data changed since the last full backup, simplifying the restore process and minimizing the risk of backup chain failures.
• Incremental backups are more efficient, but they require a full backup plus all subsequent incremental files to restore. Differential backups are easier to restore but can grow larger and consume more storage over time.
• MSPs and IT teams should choose a backup strategy based on environment-specific needs such as data growth, bandwidth availability, RTO/RPO goals, and restoration preferences. 

Incremental backup: what you need to know

Incremental backup is a data backup strategy that captures and stores only the data that has changed since the last backup—regardless of whether the previous backup was a full backup vs. an incremental backup.

Because each incremental backup includes just the changes made since the last backup, incremental backups can be executed faster, compared to full or differential backups.

How it works

Let’s imagine a situation where a full backup is performed on Day 1. It captures all of the data of a system or dataset. Then, on Day 2, an incremental backup is performed. This incremental backup only captures the changes made to the files or data since Day 1. On Day 3, another incremental backup is taken—and again, only captures the changes made since the previous day.

While incremental backups are highly efficient, restoring files after data loss can be more complex. To fully restore data, the last full backup and all subsequent incremental backups are required.

Ideal use cases

Incremental backups are the right fit for environments with:

• Large datasets and short backup windows. If your environment generates constant changes throughout the day, performing regular full backups within the available window isn’t feasible. In this case, leverage incremental backups to capture only the changes made since the last backup—and significantly reduce the overall backup time.

• Limited bandwidth. When network capacity is constrained, incremental backups reduce strain by transferring only the changed data. This results in reduced data transmission and lowers the impact on a network's resources.

• Specific RPO or RTO requirements. By capturing changes more frequently, you can reduce the potential of data loss.

• Limited storage. Maintaining multiple full backups or differential backups uses up disk space. Because incremental backups are smaller in size, they allow you to retain a longer backup history—without exhausting storage resources.

By focusing on capturing the incremental changes made, day by day, you can strike a balance between data protection and resource efficacy.

Differential backup: what you need to know

Now that we’ve covered incremental backup, what is a differential backup?

A differential backup works by capturing and storing all the data that has changed after the last full backup. Unlike incremental backups, which only back up data that has changed since the last backup of any type (full or incremental), differential backups always include all changes made since the last full backup.

This means that with each differential backup, the backup set grows larger, capturing a collection of changes since the last full backup.

How it works

Say your full backup was performed on Day 1, capturing all of your data. On Day 2, a differential backup is taken, capturing all of the changes made since Day 1. On Day 3, another differential backup is performed—and this captures the comprehensive changes made since Day 1.

The restoration process for a differential backup is relatively straightforward. To restore the data to a specific point in time, the last full backup and the latest differential backup are required. By combining the last full backup with the latest differential backup, the system can be restored to the desired state.

Ideal use cases

Differential backups are ideal for:

• Frequent data changes. Daily differential backups are an effective solution for environments with frequently file updates and modifications throughout the day. It enables you to quickly capture changes and ensures that data is protected without the overhead of performing full backups regularly.
• Regulatory compliance. For organizations subject to strict regulatory compliance requirements (or MSPs supporting clients in these industries), maintaining a comprehensive backup history is essential. A differential backup strategy should be used to create a series of backups—capturing all changes since the last full backup. This approach makes it easier to maintain long-term retention of data for compliance purposes, as each differential backup includes a snapshot of data at different points in time.
• Rapid recovery. In situations where rapid recovery is crucial, such as when dealing with critical systems or time-sensitive projects, differential backups can provide a better option than incremental backups. Since each differential backup includes all changes since the last full backup, restoring the system requires only the last full backup and the latest differential backup, simplifying the recovery process.

When considering your backup options, a differential backup strategy is a practical and efficient data protection solution for environments with frequent data updates, regulatory compliance requirements, and the need for rapid recovery in disaster scenarios.

Incremental vs. differential backup: how do they compare?

We’ve covered the basics, so let’s see how the pros and cons of each backup method stack up side-by-side.

Incremental backup

Advantages:

• Backup size: Incremental backups have smaller backup sizes compared to full backups and differential backups. This reduces storage requirements and backup time.
• Backup speed: Since only the changes made since the last backup are captured, incremental backups are the faster option compared to full backups and differential backups.
• Bandwidth efficiency: Incremental backups transfer only the changed data, making them more bandwidth-efficient, which is advantageous in low-bandwidth environments or remote backup scenarios.
• Granular recovery: Incremental backups provide more granular recovery options, allowing users to restore data to specific points in time between full backups.

Shortcomings:

• Complexity in restoration: Incremental backups require the last full backup and all subsequent incremental backups for a complete restoration. This complexity can lengthen the restoration process compared to differential backups.
• Dependency on previous backups: A chain of incremental backups relies on previous backups, so a failure in any one backup can affect the ability to restore data from subsequent backups in the chain.
• Backup chain length: Over time, the number of incremental backups in the chain can grow, potentially increasing the time required for full restoration.

Differential backup

Advantages:

• Faster restoration: Differential backups require only the last full backup and the latest differential backup for restoration, making the restoration process simpler and quicker compared to incremental backups.
• Fewer backup files: As each differential backup captures all changes since the last full backup, there are fewer files in the backup chain compared to incremental backups.
• Lesser dependency: A single differential backup is not dependent on previous backups, reducing the risk of data loss in the event of a backup failure.

Shortcomings:

• Backup size growth: Differential backups grow in size with each backup, capturing all changes since the last full backup. As a result, they can become larger than incremental backups over time.
• Slower backup process: Compared to incremental backups, differential backups take longer to complete since they capture all changes since the last full backup, irrespective of when the last backup was taken.
• Higher storage requirement: Over time, the storage requirement for differential backups can become significant, especially when there are frequent data changes.

Choosing the right backup option

When evaluating which method to deploy, consider these crucial factors to help determine whether an incremental or a differential backup is most effective.

• Data size and growth rate: If your data set is large and growing rapidly, incremental backups may be preferable due to their smaller backup sizes and faster completion times.
• Backup frequency: If your environment has frequent data changes throughout the day, an incremental backup strategy can effectively capture these changes without exhausting resources.
• Recovery point objective (RPO) or recovery time objective (RTO): Because incremental backups offer the most frequent capture of data changes, this option is recommended for environments with strict or robust RPO and RTO requirements.
• Network bandwidth and speed requirements: Incremental backups are more efficient for bandwidth, which makes them the ideal choice for environments with limited network resources.
• Storage capacity: If you have limited resources, incremental backups are preferred due to their smaller backup sizes.
• Restoration needs: What is your tolerance for restoration complexity? Incremental backups are known to involve a more complex restoration process in comparison to differential backups.
• Data retention: If long-term data retention is a top priority, differential backups are more manageable.
• IT staffing and processes: If restoration and testing resources are limited, differential backups may provide a more reliable recovery option with fewer points of failure.

Both incremental and differential backups provide a secure foundation for protecting organizational data, whether you’re managing internal IT infrastructure or delivering services as an MSP.

Solutions to manage your incremental and differential backup plans

Regardless of the specific backup configuration chosen, both incremental and differential backup solutions play a critical role in ensuring the effective data protection. Backup solutions act as a safety net, providing a means to recover data and systems in the event of data loss, hardware failure, software corruption, accidental deletions, cyberattacks, or other natural disasters.

ConnectWise provides comprehensive BCDR solutions for MSPs and IT teams looking to strengthen data protection, simplify management, and ensure rapid recovery. Our software solutions help MSPs deliver reliable backup services and give IT teams the tools to safeguard internal systems, reduce downtime, and strengthen resilience against cyberthreats. Watch an on-demand demo of BCDR solutions from ConnectWise to get started today.