HP1920, LACP, stacking

[andrenth]

Hello

I currently have my switches connected in a "fat tree" architecture. I receive two uplink cables and each is connected to an HP1920 switch. These uplink switches are the root of the fat tree. Then each server rack has one switch which connects to both root switches. This is shown graphically at http://pastebin.com/AxyS9gu1

We're now moving to a new datacenter, which delivers their uplink via LACP. This means that I need to figure out a way to achieve redundancy with the uplink switches, considering that LACP requires that the two cables are connected to the same switch.

Ideally I'd be able to do something like this: http://pastebin.com/d0yjJL7M

However, I believe 1920s won't support that configuration (i.e. two stacked switches, each receiving one of the LACP cables). From what I researched, I'd need a 2920 for that. Is that correct?

Other than buying new equipments, do you guys see any option for providing redundancy in this scenario?

Thanks in advance,
Andre

[16again]

Why not just terminate the LACP trunk on switch 3 ?
Sw3 is already a SPOF, since server(s) aren't connected to other switches