Front-End Connectivity ModesDell Compellent 101Failover Behavior for Legacy Mode and Virtual Port ModeLegacy mode and virtual port mode behave differently during failure conditions becausethey use different mechanisms to provide fault tolerance.Scenario Virtual Port Mode Legacy ModeNormal operating conditions All ports are active and pass IO. • Primary ports pass IO.• Reserved ports remain in astandby mode until acontroller failure.A controller fails in a dual‐controller Storage CenterVirtual ports on the failedcontroller move to physical portson the functioning controller.Primary ports on the failedcontroller fail over to reservedports on the functioningcontroller.A single port fails (single‐ ordual‐controller StorageCenter)An individual port fails over toanother port in the fault domain.The port does not fail overbecause there was no controllerfailure. If a second path isavailable, MPIO software on theserver provides fault tolerance.Note: In Legacy mode, reserve ports and primary ports reside on separatecontrollers, providing controller‐level failover only. Legacy mode does not provideport‐level failover.
