Hi,
Let me share our experience with VDI and spice. First I do not have a solution to make the spice server more reactive.
Here is our current infra:
12 hosts with Xeon processor with 10G port and a couple of hundreds of memory per host.
This runs around 55 VMs 40 of them are servers vms and 15 desktops VMs . running Ubuntu/Windows
The desktop vms are accessed from a Windows machine on a 1G network.
Laggy for us is if we move a window and the mouse does not precisely move with the windows then it is laggy.
So with our current setup spice server is not usable. The offset of the mouse vs windows is a couple a inches. It is like moving a window attached to an elastic band.
RDP to a windows vm is snappy.
RDP to a xrdp server on Ubuntu running Gnome is laaagy.
The only usable remote desktop protocol we are able to use is
Xpra and the NX protocol.
Xpra in seamless mode is by far the snapiest and faster protocol. The problem with Xpra is some stability issues. But the support from the dev is amazing.
The NX protocol is also a good choice. The x2go variant is a good seamless option. It is as fast as Xpra but the Xpra has a sharper rendering.
There is also nomachine software( creator of the NX protocol) that has the best desktop experience. I think you can try it for free for 30 days and the licencing is not that expensive.
I always ask myself the question why RDP on windows is way better than the other options. Even the xrdp server is no match even using the same windows client. Is this related to the windows env.(i.e gnome) or the Xserver..
So if you find a way to make the spice server more snappy i would like to know.
Maybe a seamless mode for spice server could help.
Regards.