Protecting your valuable data is paramount, and implementing a robust backup strategy is non-negotiable. While full backups are essential, they can consume significant storage space over time. This is where incremental backups shine, offering a smart and efficient way to save multiple versions of your data without duplicating files that haven’t changed.
A powerful tool for creating these efficient backups on Linux systems is rsync. Beyond its basic file synchronization capabilities, rsync, when used with the right options, can create snapshots of your data over time. The key to achieving space-saving incremental backups with rsync lies in its ability to create hard links.
By specifying a previous backup as a reference point using the --link-dest option, rsync will only copy new or modified files. For files that haven’t changed, it creates hard links from the new backup directory back to the identical files in the reference directory. This means the identical file content exists only once on disk, dramatically reducing the disk space required for each subsequent backup.
To automate this process and ensure your backups happen regularly without manual intervention, you can utilize the cron utility. cron is the standard job scheduling tool on Linux, allowing you to run commands at specific times or intervals. By creating a simple cron job, you can schedule your rsync command to execute daily, weekly, or as frequently as your data recovery requirements dictate.
Setting up the rsync command within a cron job involves defining the source directory, the destination directory (often timestamped for easy identification of each snapshot), and the crucial --link-dest option pointing to the previous backup. Adding options like -a (archive mode) to preserve permissions and timestamps, and potentially -v for verbose output or -h for human-readable sizes, enhances the backup process.
Using rsync with hard links and scheduling it with cron provides a flexible and efficient backup solution. It allows you to maintain multiple recovery points (snapshots) while minimizing the disk space footprint compared to traditional full or differential backups. This approach is a cornerstone for effective data protection on Linux systems. Remember to periodically test your restoration process to ensure your backups are valid and you can recover your data successfully when needed.
Source: https://www.tecmint.com/linux-rsync-incremental-backup-cron/
