Network traffic flow in a VIF of VIFs

I wonder anyone has any experience/expertise they can share.

We’ve a FAS3240 HA pair running 8.0.2P6 7-mode, but likely to be upgraded to 8.1.3 7-mode soon. Currently each is connected to a separate Juniper switch stack via an LACP VIF of two 10Gb connections, as in the first diagram. As switch stack reboots (for firmware upgrade etc.), cause an outage, what I want to do is connect them as in the second diagram and then have a VIF of VIFS. I understand this is possible, but the question is how do you ensure that under normal circumstances traffic only uses the 2 x 10Gb connection. With Juniper switches you can’t span LACP groups across switch stacks.

Re: Network traffic flow in a VIF of VIFs

You designate 10G interface (ifgrp) as favored using “ifgrp favor …” command. See Network Management Guide, Selecting an active interface in a single-mode interface group.