How do you monitor and manage switch stack performance and health?

1 Switch stack overview

A switch stack is a group of switches that operate as a single logical unit, sharing a common configuration, management, and routing information. Switch stacks can have up to nine members, depending on the model and software version. The switches are connected by stack cables that form a ring topology, allowing data and control traffic to flow in both directions. The switch stack elects one member as the master, which controls the stack operation and configuration. The other members are slaves, which follow the master's instructions and forward data traffic.

2 Stack status and membership

To monitor the stack status and membership, you can use the show switch command, which displays information such as the stack role, priority, state, MAC address, and software version of each member. You can also use the show switch detail command, which provides more details such as the stack port status, stack protocol version, and uptime of each member. You can use these commands to verify that all members are present, active, and synchronized with the master.

3 Stack configuration and verification

To manage the stack configuration, you can use the global configuration mode of the master switch, which applies the changes to all members. You can use the show running-config or show startup-config commands to view the current or saved configuration of the stack. You can also use the show switch provision command to see the provisioned configuration of each member, which specifies the model and software version expected by the master. You can use these commands to verify that the stack configuration is consistent and correct.

4 Stack performance and utilization

To monitor the stack performance and utilization, you can use the show processes cpu command, which displays the CPU usage of each member and the total stack. You can also use the show processes memory command, which displays the memory usage of each member and the total stack. You can use these commands to identify any high CPU or memory utilization issues that may affect the stack operation. You can also use the show interfaces command, which displays the status, speed, duplex, and statistics of each interface on the stack. You can use this command to check the bandwidth, errors, and collisions of each interface.

5 Stack troubleshooting and recovery

To troubleshoot and recover from stack issues, you can use the show logging command, which displays the log messages generated by the stack. You can use this command to identify any errors, warnings, or events that may indicate a problem with the stack operation or configuration. You can also use the show tech-support command, which collects various diagnostic information from the stack and displays it on the screen or saves it to a file. You can use this command to gather data for further analysis or support. If a member fails or leaves the stack, the stack will automatically adjust and continue to operate with the remaining members. You can use the switch renumber command to change the member number of a new or replaced switch, and the switch provision command to provision it with the correct model and software version.

6 Stack best practices and recommendations

To ensure the stack performance and health is optimized, you should adhere to some best practices and recommendations. This includes using the same model and software version for all members of the stack, as well as using high-quality and compatible stack cables and connectors. Additionally, it is important to use the recommended stack cable length and avoid excessive bends or twists. Loops or breaks in the stack ring topology should also be avoided. Furthermore, you should set a high priority value for the desired master switch and a low priority value for the backup master switch. The auto-upgrade and auto-advise features should be used to update and align the software version of new or replaced switches, while the reload slot command can be used to reload a specific member of the stack. Finally, you should use the redundancy mode sso command to enable stateful switchover (SSO) for faster failover and recovery.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?