With Kubernetes powering more applications, implementing robust Kubernetes backup strategies like incremental and full backups plays a key role in ensuring business continuity. For organizations leveraging containerized environments, having a backup built for Kubernetes is essential to protect workloads effectively.
In this post, we’ll understand incremental and differential backup strategies and their advantages, disadvantages, and best practices.
Types of Backups
Not all backup strategies are the same for safeguarding data and ensuring business continuity. Different types of backups offer varying levels of coverage, efficiency, and speed. Understanding the types of backup methods is essential. There are three main types:
Full Backup
A full backup is a complete backup of all the data at a time; you get the whole system copy saved. It captures all files and resources regardless of when they were last backed up or modified. This type of backup ensures that all data is stored, making it a fundamental part of most backup strategies. However, full backups can be time-consuming and resource-intensive.
Incremental Backup
Incremental Backup only copies the files modified or changed since the last backup (either full or incremental). For example, if you perform a full backup on Monday and an incremental backup on Tuesday, the Tuesday backup will only include files altered since Monday’s full backup. If you take an incremental backup on Wednesday, it will include only the changes since Tuesday.
Differential Backup
Differential Backup only copies the files that are added or modified from the last full backup. For example, if a full backup is performed on Monday, a differential backup on Tuesday will include all files changed or added since Monday. If you perform another differential backup on Wednesday, it will again include all the changes made since Monday’s full backup, not just those made since Tuesday.
The diagram below shows you the difference between Incremental and Differential backups.
In the following sections, we’ll focus on understanding incremental and differential backups.
Understanding Incremental Backups
Definition
Incremental backup is a backup type in which only the data that has changed since the last backup is saved. This method minimizes both the time and storage needed for backups by focusing solely on modified files.
Advantages of Incremental Backups
- Efficiency in Time and Storage: Since only changes are backed up, the process is quicker and requires less storage space than full or differential backups.
- Faster Backup Process: Incremental backups are ideal for situations with frequent data changes and limited time for backup. Since only the latest changes are saved, the process is quicker compared to performing full backups, which are time-consuming.
Disadvantages of Incremental Backups
- Complex Restoration: To restore a system, you need the most recent full backup followed by all incremental backups in the correct sequence. If any of the sequential backups get corrupted, this can complicate the recovery process and increase the risk of failure.
- Increased Risk of Data Loss: If one incremental backup in the chain is missing or corrupted, the entire backup set may become unusable.
Understanding Differential Backups
Definition
A differential backup stores changes made since the last full backup. Unlike incremental backups, differential backups accumulate changes without resetting after each backup cycle. This provides a simpler restoration process, as you only need the most recent full and differential backup to restore data.
Advantages of Differential Backups
- Simpler Restoration: Recovery is faster and easier because you only need the most recent full backup and the latest differential backup to restore the system.
- Intermediate Storage and Time Efficiency: Differential backups are more efficient than full backups in terms of time and storage, but they do grow larger over time as more changes are captured. For example, If your last full backup was on Monday, a differential backup on Friday would copy all changes since Monday. If you took another differential backup on Saturday, it would also copy all changes since Monday. The backup file size would increase progressively until the next full backup.
Disadvantages of Differential Backups
- Storage Requirements: As the number of changes grows, the size of differential backups increases. Over time, this can require significantly more storage than incremental backups.
- Longer Backup Time: As more data is modified, differential backups can become progressively slower, although they will still be faster than full backups.
Incremental vs Differential Backups: Key Differences
As discussed in the previous section, both incremental and differential backups have strengths and weaknesses. These affect the backup speed, storage requirements, and restore times. The table below highlights the main differences between incremental and differential backups.
| Parameter | Incremental Backup | Differential Backup |
|---|---|---|
| Backup Size | Smaller, as only recent changes are saved | Larger, increases over time as more changes are accumulated |
| Backup Speed | Faster, since fewer files are copied | Slower compared to incremental, as more data is backed up |
| Storage Requirements | Lower, due to smaller backup sizes | Higher, as more data is stored cumulatively |
| Storage Allotment/Budget | Cost-efficient, suitable for organizations with limited storage budgets | More storage-intensive, may require larger budgets |
| Restore Speed | Slower, as it requires restoring the full backup and all incremental backups in sequence | Faster, since only the full backup and the latest differential backup are needed |
| Risk of Data Loss | Higher, if any incremental backup in the sequence is corrupt | Lower, since the last differential backup contains all changes since the last full backup |
| Regulatory Compliance | More suitable for industries with fewer regulations | Preferred in industries where faster recovery is mandated, such as banking and healthcare |
| Organizational Compliance | May need more frequent full backups to comply with internal policies (e.g., company policies for data retention) | Aligns well with policies that prioritize fast data restoration |
Use Cases and Best Practices
Whether you choose an incremental or differential backup strategy depends on your specific needs and circumstances. Each approach has some ideal scenarios where it excels in balancing speed, storage, and recovery time. In this section, we’ll examine ideal scenarios for each approach.
Ideal Scenario for Incremental Backups
Incremental backups are an efficient backup method that captures only the data that has changed since the last backup—whether that backup was full or incremental. This method is ideal for organizations that need to minimize backup time and storage consumption while maintaining up-to-date recovery options. Let’s look at when to use incremental backups.
- Frequent Changes: When data undergoes frequent changes, and real-time backups are crucial, incremental backups are helpful. For instance, production databases often have small but consistent changes happen throughout the day.
- Limited Storage: If storage is a concern, incremental backups are advantageous since they use less space than full or differential backups.
- Time-sensitive Operations: In scenarios where minimizing backup time is critical, such as when running backups during operational hours or with limited backup windows.
- Kubernetes Applications: In Kubernetes, incremental backups are effective when managing stateful workloads with persistent storage that supports snapshots or with applications like databases that have built-in support for incremental backup. This ensures efficient recovery of container-specific data with minimal downtime.
Ideal Scenario for Differential Backups
Differential backups capture all changes made since the last full backup. These are larger than incremental backups but allow quicker recovery than restoring from a series of incremental backups. Let’s look at when to use it.
- Less Frequent Changes: When data changes less frequently, differential backups can be more efficient, balancing storage and restore time. This is especially true for systems that experience moderate change and don’t need daily full backups.
- Simpler Recovery: When a straightforward recovery process is necessary, differential backups help by requiring only the last full backup and the most recent differential backup, reducing complexity during recovery. For example, you could just archive the images or audio files for one time if they don’t change over time, saving you space and providing your critical product data with minimal downtime recovery.
- Moderate Storage Capacity: If storage is not a concern, and organizations want to minimize restore time, differential backups offer an effective balance.
- Kubernetes Clusters with Stateful Applications: Differential backups are suitable when faster recovery is required for clusters hosting complex applications with large, stateful datasets.
Best Practices for Efficient Backup Management
Given the dynamic and distributed nature of Kubernetes, backup solutions should account for the containerized environments and the underlying orchestration. Below are some best practices tailored to Kubernetes backups:
- Application-Aware Backups: Ensuring that backups are “application-aware” means that your solution understands the application’s structure and dependencies within the Kubernetes environment. For example, if a database application runs within a pod, the backup should capture not just the data but also the application state to ensure seamless recovery.
- Container Granular Backups: Backup solutions should offer container-level granularity, allowing users to back up and restore specific containers within a pod rather than the entire cluster. This reduces recovery time, storage usage, and the overall impact on the infrastructure.
- 3-2-1 Backup Strategy for Kubernetes: Implementing the 3-2-1 backup strategy—where you have three copies of data, two on different storage media, and one offsite—is vital for ensuring reliable backup and recovery. This practice mitigates risks of data loss due to corruption, hardware failure, or other disasters, especially in a dynamic Kubernetes environment.
Backup Tools and Software
Features to Look For in a Kubernetes Backup Solution
Choosing the right Kubernetes backup tool requires attention to several features that ensure data protection, scalability, and ease of management:
- Application-Aware: The backup solution should be application-aware, ensuring it understands containerized applications’ underlying structure and dependencies. This includes awareness of how the application handles data, where it’s stored, and how to quiesce it for a consistent backup.
- Container Granular: Kubernetes backups should be container granular, allowing users to back up specific containers or pods rather than the entire application or cluster. This feature ensures that critical application components can be restored quickly, reducing downtime in case of an incident.
- Security: Security features in backup tools are non-negotiable, especially in cloud-native environments like Kubernetes. Look for tools that offer:
- Role-Based Access Control (RBAC): Ensures that only authorized users can perform backups or restores, safeguarding sensitive data from unauthorized access.
- Encryption: Both in-flight and at-rest encryption are critical for protecting backup data from theft or tampering.
- Ransomware Protection: Advanced tools offer ransomware protection, detecting and stopping malicious activities that aim to corrupt or delete backup data.
- Application Migration: Modern Kubernetes backup tools should also support application migration, enabling users to move applications between clusters, cloud environments, or from on-premises infrastructure to the cloud. This ensures flexibility and scalability, which is crucial for growing organizations.
By considering these features and best practices, organizations can ensure that their Kubernetes backup solutions are efficient, reliable, and secure.
Conclusion
Backup strategies play a vital role in safeguarding data and ensuring business continuity. By understanding the differences, organizations can make informed decisions that optimize backup performance, storage efficiency, and restore times.
Summary of Incremental and Differential Backups
Incremental backups focus on saving storage space and speeding up the backup process by only capturing changes since the last backup. In contrast, differential backups offer faster recovery times by storing all changes since the last full backup.
Choosing the Right Backup Strategy for Your Needs
After understanding the differences between the backup strategies, selecting the most suitable ones depends on your environment—data size, frequency of changes, available storage, and restore times. Organizations with tight storage constraints may prefer incremental backups, while organizations that prefer faster restores may prefer differential backups. In some cases, both these methods can be combined to provide a balanced approach.
Learn More
Well-thought out backup strategies are essential for robust data protection and disaster recovery. Explore Portworx’s solutions to learn more about optimizing your data management practices and crafting your backup strategy.
You can try Portworx for free and experience how our data management platform can simplify your backup and recovery processes. If you have any questions or need guidance on implementing the best backup strategy for your organization, refer to Portwork backup documentation or contact our experts.