Managing traditional stack partitioning

Ring topology stacks do not partition when a stack member fails. Operation is interrupted briefly while the stack recalculates a new path. Ring topologies are more stable than linear topologies because they provide redundant pathways in case of accidental failure.

When a unit in a traditional stack with a linear topology fails, the traditional stack divides (partitions) into two or more separate stacks that all have the same configuration. This may cause an IP address conflict in the network. To keep the stacks separate, change the IP address of each new stack.

When a stack breaks into partitions, the partition with the active controller remains operational. If a partition contains the standby controller, this partition becomes operational because the standby controller assumes the active role and reloads the partition units. However, if hitless failover is enabled, the partition units are not reloaded. A partition without an active controller or standby controller does not function. To reconfigure these units to act in standalone mode, you must first enter a stack unconfigure me command on each unit.

To reverse the partitioning, reconnect all of the units into the original stack topology using the stacking ports. This is the same as merging stacks. If the original active controller again has the highest priority, it regains its role. If two partition active controllers have the same priority, the active controller with the most stack members is elected. This process helps minimize traffic interruption.