I am about to split a large database into a bunch of federated instances. Currently, most of the primary keys are auto-generated identity ints. Obviously, that's not going to work in a federated setup.
I've read people using auto-generated GUIDs to replace the ints, but that data type has well-known performance sapping problems on its own.
What are some of the strategies I can use for having unique values for primary keys across federated members?