I'm building a Debian file and media server with a 1 TB NVMe drive for the operating system and services, plus two 14 TB hard drives for storage. I'd like to periodically back up the data from one 14 TB drive to the other, but I don't want the backup job to noticeably affect server performance. Is there a tool or approach that can run backups only during idle hours or when the server isn't being used?
1 Answer
You could schedule an rsync job with cron during a time when the server is normally idle, such as 3–5 AM. Running it with low CPU and I/O priority using tools like `nice` and `ionice` can further reduce its impact. Keep in mind that a simple mirror or RAID setup is not the same as a backup: accidental deletions and corrupted files can be copied to the other disk.
RAID 1 would provide redundancy if a drive fails, but it wouldn’t protect against accidental deletion or other changes. Keeping a separate scheduled copy makes more sense if the goal is to fall back to an earlier or independent copy.