How many of the switches in a stacked FlexStack configuration run STP?

In a stacked FlexStack configuration, only one switch actively runs the Spanning Tree Protocol (STP) for the entire stack. This designated switch is responsible for managing the STP operations and maintaining the network topology to prevent loops.

The other switches in the stack do not run STP independently; instead, they rely on the designated switch to handle STP updates and information. This setup simplifies the management of the network by centralizing STP operations to one switch, which can effectively coordinate STP across the entire stack, enhance performance, and reduce unnecessary overhead.

Therefore, having just one switch running STP in a stacked FlexStack configuration is advantageous as it minimizes the complexity and provides a streamlined process for managing the layer 2 topology.