Empty hard drive shows gigabytes of used space?

[Jaybau]

I have a hard drive that says there's 41.9 GB used space.  However, when I view/browse the drive, there's zero objects.

Is this normal?

What is the 41.2GB used for?

Is my drive empty or not?

More info:  I recently moved objects from Disk2 to Disk1 (via mc).

 

 

 

Thanks.

 

[Frank1940]

This is the space required for the file system and overhead to support recovery from file system errors.   XFS has fairly robust recovery from file system errors and the data to be able to do this requires dedicated disk storage space.

[JorgeB]

Like mentioned, it's normal with XFS, especially since it started supporting reflinks.

[JonathanM]

23 hours ago, Jaybau said:

What is the 41.2GB used for?

Think of the hard drive as an empty room. You could just throw stacks of papers in the room when you want to store info, but finding any specific piece of paper would be a nightmare. Now fill the room with filing cabinets and folders, with a dedicated area just to record the title of each piece of paper, and which drawer and folder to find it in. That filing system definitely takes up space, and the more info is kept on each paper, along with possible multiple copies of the table of contents with cross checking just in case one gets messed up, and you can see why there is so much space taken up on an "empty" hard drive.

 

The file system type, XFS, BTRFS, NTFS, FAT32, each one keeps up with all that info in a different way, and each has strengths and weaknesses. When a drive becomes unmountable, it means the filing system that keeps up with the location and extra info like name and location on the drive is messed up in some way. If you format the drive, you tell the system to clean out the table of contents, forget about anything that was ever stored, and start over with a fresh blank slate. It doesn't actually throw away the virtual pieces of paper, just overwrites them as the space is called for.