This week I was investigating some imbalance in size on two (scale out) repositories. Every repository gets the backup of a subset of all VMs and copy these to the second repository. And vice versa. So in theory, both repositories should be very similarly utilized. But when you look at volume properties, this is not the case. We see quite a large difference. So I used PowerShell to query VBR and sum all data of each VM on both repositories (I will post some code snippets next week). And I found out, VBR does not know about a notable amount of data (VBR-query showed much less used data than volume properties did).
So there seems to be backup data, VBR is not aware of. I call these files orphaned files. What are your experiences with orphaned files? Do your see them very often or not at all? Or are you not aware of their existence? Please let us know.
rUpdate] See my new blog post on how to find orphaned backup files