Infrastructure

Science metadata is technically replicated to all CNs, which means that system metadata for science metadata should also be updated with the CN replica information as the document is replicated across CNs. This will likely cause a race condition as each CN updates the replica information in the system metadata as it is retrieved and stored during the CN replication process. This can be avoided by either a) indicating a generic rather than specific CN (e.g. the CN URL might be cn.dataone.org rather than a specific CN); or b) adding all CNs as replicas as the system metadata is added to the first CN after initial harvest. Option b is simplest, though has a chance of failure as the object may not yet be replicated to other CNs before being accessed.

This will likely depend upon implementation of Messaging Service and/or evaluation of distributed locking mechanism...