Administrator Guide

3 Completely cable the stacking connections, making sure the redundant link is also in place.
Two operational stacks can also be merged by reconnecting stack cables without powering down units in
either stack. Connecting a powered-up standalone unit to an existing stack leads to same behavior as when
merging two operational stacks. In such cases, Manager re-election is done and the Manager with the higher
MAC address wins the election. The losing stack manager resets itself and all its member units. After the reset,
all the losing stack members join the winning stack to form a single stack. The winning stack remains
functional through the merge process. If the stack merge is performed in this way, then it is strongly
recommended that the user set the admin management preference of the desired winner stack manager to a
higher value than the stack manager that should lose the election.
NOTE: In case of a stack, when one unit member resets and joins the stack, momentary drops will be
observed, which is recovered after few seconds.
Verifying a Stack Configuration
The following lists the status of a stacked switch according to the color of the System Status light emitting
diodes (LEDs) on its front panel.
• Blue indicates the switch is operating as the stack master or as a standalone unit.
• Off indicates the switch is a member or standby unit.
• Amber indicates the switch is booting or a failure condition has occurred.
Using Show Commands
To display information on the stack configuration, use the show commands on the master switch.
• Displays stacking roles (master, standby, and member units) and the stack MAC address.
show system [brief]
• Displays the stack groups allocated on a stacked switch. The range is from 0 to 5.
show system stack-unit unit-number stack-group configured
• Displays the port numbers that correspond to the stack groups on a switch. The valid stack-unit numbers
are from 0 to 5.
show system stack-unit unit-number stack-group
• Displays the type of stack topology (ring or daisy chain) with a list of all stacked ports, port status, link
speed, and peer stack-unit connection.
show system stack-ports [status | topology]
Troubleshooting a Switch Stack
To perform troubleshooting operations on a switch stack, use the following commands on the master switch.
1 Displays the status of stacked ports on stack units.
show system stack-ports
2 Displays the master standby unit status, failover configuration, and result of the last master-standby
synchronization; allows you to verify the readiness for a stack failover.
Stacking 858