When using VLANs in a multi-switchcore setup, we currently let every defined VLAN span the backplane of every switchcore.
This may lead to less capacity for good traffic, if the backplane becomes flooded with "VLAN traffic" going to switchcores where there is no port on associated.
Finding out what ports on different switchcores (as well as virtual ports in CPU) are associated with each VLAN, and limit the VLAN span between these switchcores (and possibly CPU) would be beneficial.