It’s probably a silly question, but is Kopia SMR (hdd recording tech) aware (or it can be)? Or this stuff is just at file system level and backup software has nothing to do with that? I’m asking because more and more and bigger and bigger SMR disk appears on the market.
SMR makes trouble for ZFS (or similar filesystems) that gluing multiple drives in a pool(s). kopia is backup tool that seats on top of filesystems, so this SMR problem isn’t related to kopia at all. As far SMR drive works alone, they are fine, besides of fact that when drive start overwriting previous content it became slow, but I don’t think it is a problem for backup purposes since it isn’t time critical process. As about recovery, SMR drives working at full speed in reading mode always.
I recommend everyone to stay away from SMR drives if at all possible.
Even if things are somewhat SMR-aware, those drives are more or less built to create salty tears for administrators in the future.
They are cheap but you will be paying the price for SMR when you need to make filesystem checks or whatever method your filesystem uses for recovery. I’m quite certain kopias repository maintenance is one of those things SMR drive will not like, when you repack blobs and edit indexes and so on.