The “Used Space” column in the Storage Summary repositories table – what does it represent

This column is meant to represent the artifact size of a repository according to the representation in the Tree Browser (if you were to sum up the size of all binaries in the Tree Browser in a specific repository, this is the number you will have come up with). 

By having it this way, you can also assess how much space you "saved" by having a checkum-based storage, when you compare it with the "Binaries Size" field, which isn't bound to a specific repository. This is due to the fact that in a checksum-based storage, the binary file does not necessarily have a 1:1 relation with the amount of DB references. 

 

Additionally, it is convenient to know what is the export size of the corresponding repository for situations where you need to have a particular repository exported.