Brocade FastIron Ethernet Switch Stacking Configuration Guide - Manual (Page 95)

More about traditional stack technology
This section discusses stacking technology in greater detail than the information presented in the
previous sections.
Configuration, startup configuration files, and stacking flash
Stacking system behavior is defined by the runtime configuration, which can be displayed using the
show run command. The write memory command stores the runtime configuration in a flash file called
startup-config.txt. During bootup, the system reads and applies the startup-config.txt file to the runtime
configuration. The startup-config.txt file can be shown using the show config command.
The stacking system installs a stacking.boot file on each unit that tells the unit what its role is during the
boot process. The stacking.boot file is generated whenever there is an election that defines the roles for
all units.
When an active controller is booted, or a write memory command is issued, the active controller
synchronizes its startup-config.txt file to every stack unit. The original startup-config.txt files in the
standby controller and other stack members are renamed to startup-config.old . If you issue the stack
unconfigure me command on the standby controller or stack member directly, these units will recover
their original startup-config.txt files and reboot as standalone devices. If you enter the stack
unconfigure all command from the active controller all devices will recover their old startup-config.txt
files and become standalone devices. When this happens, the startup-config.old file is renamed to
startup-config.txt , and the stacking.boot file is removed.
Whenever a change is made to the configuration of a stack unit, such as priority, (which could affect
stack elections) an election is held, and the result is written into the stacking.boot file. A prompt
message appears on the console that suggests you do a write memory. For an active controller role
change to take effect, you will need to reset the entire stack.
If you do not do a write memory, and reset the stack, the stack units will continue to operate in their
roles as defined by the stacking.boot file. After the reset, each unit readjusts based on the current
runtime configuration. However, you may get different results depending on what has not been saved. If
you have renumbered the stack unit IDs, you may see a configuration mismatch, because your changes
no longer match the active controller configuration.
If you change priorities to elect an active controller, the new active controller will assume its role after a
reboot whether you have done a write memory or not. If you do not save your priority change before
the next reboot, the reboot will trigger an election that may result in a different winner based on the
priority in the unsaved configuration. The new winner assumes its role after the next reboot.
If you change the stacking port configuration and do not save your changes, you may encounter
connectivity errors. To recover from a configuration error, run secure-setup to define the correct
stacking port.
NOTE
You should always do a write memory after making stacking-related configuration changes such as
priority and stacking ports. If you do not want to keep the changes, change the configuration back to the
previous version, and do a write memory. Do not discard configuration changes by using the reset
without a write memory.
More about traditional stack technology
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