Snapshot larger than underlying directory

Probably a stupid question but in my latest daily run of making a snapshot while running kopia says estimated size is 135gb despite the underlying data only being about 123gb. I thought maybe the estimate is just a bit off but when i look at the snapshot in kopia UI it shows indeed 135. I could restore the whole thing and look for differences but i figured it’d be easier to ask here first.

I figure possibly that i moved a whole bunch of stuff and i have to wait for the next maintenance run to garbage collect, but that would seem to imply changing the size of a past snapshot which would be weird? What am i missing?


Not just maintenance, if you have default retention policy, than kopia would try to keep all previous versions

But why would that show up as part of the current snapshot? Surely the size of the current snapshot is everything that would be restored if i hit restore, and previous versions correspond to sizes in the other snapshots?

To clarify, i’m not talking about the size of the repository, i understand that contains data across several snapshots.

But why would that show up as part of the current snapshot?

When you doing snapshot, pay attention at the last “uploaded”, - that’s the actual “size” of the last snapshot, everything else, if not modified, it just pointers to previous blobs. It works in the same way as hard links, if content itself is the same, you just adding a name to a thing, a pointer to previously saved content.