Home > Storage > Unity XT > Data Protection > Dell Unity: Replication Technologies > Metro node
Metro node is an external hardware and software add-on feature for Unity XT for which it provides active/active synchronous replication and standard local use cases. Additionally, it also provides a solution locally with the Local mirror feature to protect data from a potential array failure. Both of these use cases provide solutions for true continuous availability with zero downtime.
Unity XT is viewed by metro node as ALUA array based on SCSI response data and therefore is required to follow the four active, four passive path connectivity rules. This rule states that both nodes of the metro node must each have four active and four passive paths to all volumes provisioned from the array. For additional information about Metro node, go to Dell Support and reference the Metro node best practices white paper.