Stack Member Priority Values - Cisco NME-16ES-1G Features Manual

Information About the Cisco EtherSwitch Service Modules
A new, out-of-the-box Cisco EtherSwitch service module (one that has not joined a switch stack or has
not been manually assigned a stack member number) ships with a default stack member number of 1.
When it joins a switch stack, its default stack member number changes to the lowest available member
number in the stack.
Stack members in the same switch stack cannot have the same stack member number. Every stack
member, including a standalone Cisco EtherSwitch service module, retains its member number until you
manually change the number or unless the number is already being used by another member in the stack.
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Stack Member Priority Values

A higher-priority value for a stack member increases its likelihood to be elected stack master and to
retain its stack member number. The priority value can be 1 to 15. The default priority value is 1. You
can display the stack member priority value by using the show switch user EXEC command.
Note We recommend assigning the highest-priority value to the Cisco EtherSwitch service module or switch
that you prefer to be the stack master. This ensures that the Cisco EtherSwitch service module is
re-elected as stack master if a re-election occurs.
You can change the priority value for a stack member by using the switch stack-member-number
priority priority-number global configuration command. Another way to change the member priority
value is by changing the SWITCH_PRIORITY environment variable.
The new priority value takes effect immediately but does not affect the current stack master. The new
priority value helps determine which stack member is elected as the new stack master when the current
stack master or the switch stack resets.
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If you manually change the stack member number by using the switch
current-stack-member-number renumber new-stack-member-number global configuration
command, the new number goes into effect after that stack member resets (or after you use the
reload slot stack-member-number privileged EXEC command) and only if that number is not
already assigned to any other members in the stack. Another way to change the stack member
number is by changing the SWITCH_NUMBER environment variable.
If the number is being used by another member in the stack, the Cisco EtherSwitch service module
or switch selects the lowest available number in the stack.
If you manually change the number of a stack member and no interface-level configuration
Note
is associated with that new member number, that stack member resets to its default
configuration. For more information about stack member numbers and configurations, see
the "Switch Stack Configuration Files" section on page
If you move a stack member to a different switch stack, the stack member retains its number only if
the number is not being used by another member in the stack. If it is being used by another member
in the stack, the Cisco EtherSwitch service module or switch selects the lowest available number in
the stack.
If you merge switch stacks, the modules that join the switch stack of a new stack master select the
the lowest available numbers in the stack. For more information about merging switch stacks, see
the "Accessing the CLI of a Specific Stack Member" section on page
Cisco EtherSwitch Service Modules Feature Guide
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