Exploring backup strategies: from traditional to index-based

Backups are a crucial topic in any tech-driven workplace, whether you're a system administrator or the developer tasked with maintaining servers. Understanding the various backup typologies and their implications is essential, and this article aims to clarify these types and introduce a new paradigm in backup solutions.

Understanding traditional backup typologies

Traditional backup methods have been extensively discussed, yet they remain foundational. There are three primary typologies you'll encounter:

• Full Backup: This method duplicates the entire production medium onto a second storage medium. It's straightforward and quick to restore but requires significant storage space.
• Incremental Backup: This starts with a full backup and only adds files that have been modified since the last backup. While it saves on storage space, the restoration process can be complex as it requires all previous incremental backups.
• Differential Backup: Similar to incremental, this method also begins with a full backup but adds all files changed since the last full backup. Differential backups are easier to restore than incremental ones, requiring only the last full backup and the latest differential backup.

Introducing index-based backup

While traditional methods are well-known, index-based backup is gaining traction. This innovative approach relies on maintaining an index to restore data, which can be a slight drawback if the index format is proprietary or complex. However, its significant advantage lies in the ability to restore deleted files efficiently.

Technologies such as restic, borgbackup, snaper (Datashelter), and Synology HyperBackup are pioneering this method. With the rise of object storage, index-based backups are becoming more feasible and scalable, with no limits on file numbers or bucket sizes. Data in an index-based system might be organized as follows:

• /data: Contains file blobs representing complete files or data blocks.
• /index: Stores indices like index_1, index_2, etc.

If you'd like to find out more about how index-based backup works, I recommend reading our dedicated article.

Conclusion: comparing backup typologies

Each backup typology offers unique advantages and challenges. The table below summarizes these to help you choose the most suitable backup strategy for your needs.