Stackwise user priority
During the Stackwise election process used to determine which switch becomes the master, the user priority is the first criterion that is examined and compared. The value can be set to anywhere between 1 and 15, where a higher value gives a higher priority. The default priority is 1.
The stack member priority value can be set using the following command:
switch stack-member-number priority new-priority-number
For example, the following command changes the priority of stack member 6 to a value of 12:
SW1(config)#switch 6 priority 12
Note that this command can only be applied from the stack master.
Links: