I asked DO about this, and their answer was that 1) data are replicated on-site (in the same data center) but are not replicated to another data center; and 2)

I asked DO about this, and their answer was that 1) data are replicated on-site (in the same data center) but are not replicated to another data center; and 2) as for now Spaces does not provide lifecycle management. As a side note, I think lifecycle management is very useful for backups. A server push its backups to the object storage, but cannot overwrite or delete previous backups. This is useful if the server is hacked...