Neki will support cross-shard ACID transactions with a combination of an external transaction coordinator and some changes to PostgreSQL itself to support this (either by engine modifications or extensions).
I expect as part of that, we'll allow users to leverage something similar to make sure that we don't get transaction tearing in backups.
I expect as part of that, we'll allow users to leverage something similar to make sure that we don't get transaction tearing in backups.