What is file versioning in the context of backups and why is it needed?

File versioning is a backup system feature that saves not only the current version of a document, but also all its previous changes. This allows the user to return to any state of a file at a specific point in time in the past, which is critically important for protection against accidental overwrites or data corruption.

Unlike simple copying, where a new file replaces the old one, versioning creates a chain of changes. If you edited a work project for a week and accidentally deleted an important fragment, the versioning feature will allow you to roll back the document to the state of three days ago while preserving all other relevant work.

To effectively organize versioning in backup systems, certain storage algorithms are usually applied. They can store either only changes between versions or full copies at specified intervals, which helps optimize the disk space used.

Configuring versioning requires a balance between a deep history of changes and available space on the drive. It is recommended to use automatic rotation, where hourly versions are kept for a day, daily versions for the past week, and weekly versions for several months.