In Vault Enterprise, the two replication methods available are 'Performance Replication' and 'Disaster Recovery Replication'. Performance Replication is used to replicate data across multiple clusters for improved read performance. Disaster Recovery Replication is used to replicate data to a different site for disaster recovery purposes. Cluster sharding and namespaces are not replication methods; Cluster sharding is related to distributing data across multiple servers, and namespaces are used for multi-tenancy within Vault. Thus, the correct choices are Performance Replication and Disaster Recovery Replication.