For postgres we send WAL files to a server in AWS which processes them. To bootstrap the database initially we sent zfs snapshots, and those WAL files are applied on an ongoing basis. If our data center were to die a horrendous fiery death, we could lose, at most, about 3 minutes of data although monitoring shows that it's closer to 30s under normal operating conditions.

For the app servers, saltstack is used and we synchronize that repository with what is needed to reproduce a production environment in AWS.

Obviously we'd have to provision servers, etc, but it's all possible in a worst-case scenario.