Dell 7000 Series manual Stack Member Failover, Failover Scenarios

Stacking Dell PowerConnect 7000 Series Switches

If PoE is enabled on a switch port shortly before a master failover and the hardware status change had not yet been communicated to the backup unit, the switch will continue to provide PoE power even though PoE is not enabled for the port in the configuration on the new master. The user can correct this configuration mismatch by re-enabling PoE on the port.

Stack Member Failover

When a unit in the stack fails, the master unit removes the failed unit from the stack. No changes or configuration settings are applied to the other stack members; however, dynamic protocols will try to re-converge as the topology could change because of the failed unit. When there are no connected ports on the failed unit, the stack will be intact without any changes.

Failover Scenarios

This section describes examples of what happens when a stack member or the master unit fails.

Scenario 1

In this example, the stack has four members that are connected through a daisy-chain.

Switch 1

Switch 2 Standby

Switch 3 Master

Switch 4

When all four units are up and running, the show switch CLI command gives the following output:

console#show switch

Switch	Managemen	Standby	Preconfig	Plugged-in	Switch	Code
	Status	Status	Model ID	Model ID	Status	Version
------	----------	-------------	--------- --------		------------ --------
1	Stack Mbr	Standby	PCT7048	PCT7048	OK	4.0.0.6
2	Stack Mbr		PCT7048	PCT7048	OK	4.0.0.6
3	Mgmt Sw		PCT7048	PCT7048	OK	4.0.0.6
4	Stack Mbr		PCT7048	PCT7048	OK	4.0.0.6

At this point, if Unit 2 is powered off or rebooted due to an unexpected failure, show switch gives the following output:

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