When working with the CyberArk Disaster Recovery (DR) solution, the services that should be running on the DR Vault are the CyberArk Vault Disaster Recovery, the PrivateArk Database, and the PrivateArk Server. These services ensure that the DR vault can operate correctly and maintain data integrity and availability during disaster recovery situations. The CyberArk Event Notification Engine is not specifically required for the DR Vault to function properly.