According to the Aruba Documentation Portal1, the Aruba CX 6200F VSF stack is a feature that allows you to create a virtual switching framework (VSF) with up to eight members that can be managed as a single logical device. The VSF stack provides benefits such as load balancing, failover, redundancy, and security.
To add a new device to the VSF stack, you need to configure the device with the VSF command vsf member and specify the type, link, and secondary-member information. The type of the new device can be one of the following: JL726A, JL726B, JL726C, or JL726D. The link is the interface that connects the new device to the existing VSF members. The secondary-member is an optional parameter that specifies which member will act as a backup in case of a failure.
1: https://www.arubanetworks.com/techdocs/AOS-CX/10.06/HTML/5200-7726/index.html 2:
https://buy.hpe.com/us/en/networking/switches/fixed-port-l3-managed-ethernet-switches/6000-switch-products/a
https://addin.co.th/shop/switch/aruba-switch/6200f-series/jl726a/