The best backup strategy for a GNU+Linux server will depend on a number of factors, including the size and complexity of the server, the criticality of the data, and the available resources. However, some general best practices for backing up a GNU+Linux server include:
Regular backups: It's important to perform regular backups of your server, depending on the frequency of updates to your data. You could choose daily, weekly or even hourly backups depending on the needs of your system.
Offsite backups: Keeping backups offsite ensures that if anything happens to your server or data center, you will still have a backup that you can recover from. Cloud storage services like object storage or local drives can be useful for offsite backups.
Use versioning: A versioning backup system can keep multiple copies of your backups, allowing you to restore previous versions of files or data if needed.
Verify backups: It's important to verify that your backups are working properly by periodically restoring data from your backup system and checking that everything is working as expected.
Encryption: Ensure that your backup files are encrypted and secure.
Backup configuration files: It's important to backup the configuration files of your server as well. This makes it easier to restore your server to its previous configuration in case of any disaster.
Automate your backups: Automating your backups ensures that you never forget to run them.
It is recommended to have a backup strategy that is comprehensive and regularly reviewed and tested to ensure that your data is protected and can be restored in case of any disaster.