Configuration Guide User guide

278 FastIron Configuration Guide
53-1002494-02
Brocade IronStack management
You can assign the highest priority value to the stack unit you want to function as the Active
Controller. When you enter a new priority value for a stack unit, that value takes effect immediately,
but does not affect the current Active Controller until the next reset. However, if you enable hitless
stacking failover, the stack unit with the highest priority will become the active controller in about
five minutes (2 minutes in the case of ICX 6430 devices). For details, refer to “Changing the priority
of a stack unit” on page 278.
You can give your Active and Standby Controllers the same priority, or different priorities (Active
highest, Standby second-highest). When Active and Standby Controllers have the same priority, if
the Active fails and the Standby takes over, then the original Active becomes operational again, it
will not be able to resume its original role if the new Active Controller has more members.
In the same situation, when the priorities of the Active and Standby Controllers are different, the
old Active Controller will regain its role and will reset the other units.
For example, suppose both Active and Standby Controllers have the same priority. If there are more
than two units in a stack and the Active Controller leaves and comes back, it cannot win back the
Active role because the new Active Controller has more members than the old Active Controller,
which has no members. In this case, both the old Active Controller and new Active Controller have
no members, so the unit with the longer up time wins the Active role. If the old Active Controller is
reset, it cannot win. If the old Active Controller is not reset, it could win due to longer up time on up
time or lower unit ID.
If you want to assign the same priority to the Active and Standby Controllers, you must do so after
the stack is formed. This prevents the intended Standby Controller from becoming the Active
Controller during stack construction.
Changing the priority of a stack member will trigger an election that takes effect immediately
unless the Active Controller role changes. If this is the case, the changes will not take effect until
after the next stack reload. However, if you enable hitless stacking failover, the stack unit with the
highest priority will become the active controller without reload.
To display stack member priority values, enter the show stack command.
Brocade(config-unit-3)# show stack
alone: standalone, D: dynamic config, S: static config
ID Type Role Mac Address Pri State Comment
1 S FCX624 active 0012.f2eb.a900 128 local Ready
2 S FCX624 standby 00f0.424f.4243 0 remote Ready, member after reload
3 S FCX624 member 001b.ed5d.a100 200 remote Ready, active after reload
Brocade(config-unit-3)#
Changing the priority of a stack unit
To change the priority value for a stack unit, enter the priority command.
Brocade(Config)# stack unit 1
Brocade(Config-unit-1)# priority 128
Once a change in priority value has taken effect, if you have enabled hitless stacking failover, the
stack unit with the highest priority will become the active controller without reload.
Syntax: priority <num>
The <num> variable is a value from 0 through 255. 255 is the highest priority.