Configuration Guide User guide

328 FastIron Configuration Guide
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More about IronStack technology
• Greater number of members - The unit that has control over the greater number of stack
members.
• Longer up time - An up time that is more than 30 seconds longer that the next one in size is
considered. Where up times are compared, there is no effect if the difference is less than 30
seconds.
• Lowest boot stack ID - The unit that has the lowest boot stack ID (1-8, 1 is the lowest).
• MAC address - The member with the lowest MAC address.
Active Controller and Standby Controller resets
If the Active Controller is reset or removed from the stack, the entire stack reloads and Active
Controller and Standby Controller elections are initiated. If the unit functioning as the previous
Active Controller is no longer part of the stack, the Standby Controller unit becomes the new Active
Controller. After a reset, if no stack member qualifies as Active Controller, the existing Standby
Controller waits 30 seconds and then assumes the role of Active Controller.
NOTE
The details in the preceding paragraph apply to the default setup, with hitless stacking failover not
enabled.
If both Active and Standby Controllers are removed the rest of the stack will continue to function
because they are operating on whatever is programmed in the hardware. The stack members will
not be able to learn any new addresses. You will see the following message every few minutes.
Stack member is non-operational because of no Active or Standby Controller
You can recover to standalone mode by “stack unconfigure me”
Use stack unconfigure me to restore the units into standalone devices with a pre-stacking
configuration.
Selecting a standby stack unit
You can choose a Standby Controller by configuring a stack unit priority to be the second highest, or
the same as the Active Controller. If the priorities are configured the same for both, when the
original Active Controller fails, the Standby Controller takes over. If the original Active Controller
becomes active again, it will not win back its active role, which helps to minimize interruption of the
stack. However, if the original Active Controller has the higher priority, it will win back its role and
reset all of the stack units.
Standby Controller election criteria
The Standby Controller election is based on the following criteria.
• The highest priority
• Bootup as Active Controller
• Bootup as Standby Controller
• The lowest boot ID
• The lowest MAC address