This KB provides information on the maximum number of Virtual Chassis members supported on the QFX5120 and some EX switch models.
How many member switches are supported in a Virtual Chassis of QFX5120 and some EX switches?
The QFX5120-32C, QFX5120-48T, and QFX5120-48Y switches support a maximum of two members in a Virtual Chassis configuration, with both members operating in the Routing Engine role.
Figure: The table above displays the maximum number of supported members in a Virtual Chassis across different models.
2026-03-30: Article visibility modified
2026-02-26 : Article Created
https://www.juniper.net/documentation/us/en/software/mist/mist-wired/topics/concept/virtual-chassis-overview.html