Using a USB Flash Drive to Automatically Stack

A USB flash drive can be used for auto-stacking on switches with or without a mode button.

You can stack 1 to 8 nodes. If you have only a single node in the stack, stacking occurs in a daisy-chain topology. If there is more than a single node in the stack topology, the stack is connected as a ring. If a ring is not detected, the automatic stacking sequence does not run when you insert the USB flash drive.

You can build a stack one node at a time by initiating automatic stacking on one switch that, after rebooting, becomes the primary node. Attaching nodes subsequently causes those nodes to join the stack.


To use automatic stacking, each switch must have the factory default configuration. If any of the switches do not have the factory configuration (directly out of the shipping box), remove any configuration and restore the factory defaults by running the command unconfigure switch {all | erase [all | nvram]} with the all option.

License level and ExtremeXOS version mismatches are automatically reconciled. However, license mismatches due to installing feature licenses cannot be resolved automatically. The applicable node is left in the failed state.

To use automatic stacking, all switches must:
  • Have the same license level.
  • Be running ExtremeXOS 31.4 or later.

    If the primary node is running a newer version of ExtremeXOS than the nodes, the nodes are upgraded to the newer ExtremeXOS version.

  • Not have an Extended Edge Switching topology.

To begin automatic stacking:

  1. Remove the switches from their boxes and mount the desired number of switches in the desired locations. For information about physically setting up switches, see ExtremeSwitching Quick Reference Guide for the switch series.
  2. Attach the stacking cables to form a ring between the switches (see Ring Topology: Recommended for Stacking).
  3. Attach the power cables to each switch, and then plug them into a power source.
  4. Wait for all switches to boot (approximately 2 minutes).
  5. Verify that there is LINK UP on all stack ports by checking the stack port LEDs.


    A single node stack (no cabling) will not have a lit LED.
  6. On the switch that is going to be the stack primary, insert the USB flash drive.

The USB flash drive must contain a file named “autoStackingMasterNode,” which invokes the auto-stacking logic. The front panel port LEDs (on the primary node) flash in an alternating pattern followed by a delayed reboot of all of the switches. The LEDs flash for approximately 15 seconds prior to reboot. After the reboot completes, the switches are stacked.



The delay for auto-stacking can be up to 5 minutes.
If the front panel port LEDs on the primary node do not flash within the 5 minute timeout period (flashing LEDs indicate that automatic stacking has been initiated), try the following:
  • Check the cabling for correct ring topology, and fix as needed (see Ring Topology: Recommended for Stacking).
  • Check that the stack port LINK UP LEDs are lit.


    A single node stack (no cabling) will not have a lit LED.

If you can verify that both the cabling and the LINK UP LEDs are lit, then further troubleshooting requires accessing the switch with a console or by cloud access to check the switch's error log.