For months I've off and on talked with the other Citrix admin at my place of work and we both agree that being able to migrate users from one Citrix server to another would be the ultimate. Naturally this would be extremely tough to do - unless....
Unless each terminal services session is in its own right a self contained virtual machine that is merely utilizing the host as the hypervisor, even though the host is in itself not necessarily dedicated to being a hypervisor. That virtual machine TS session can then be migrated to a new host in the same manner as a guest in ESX is migrated to another host. Technically whats the difference? There would need to be a lot more checks in place for host to host migration, but what if you are coupling terminal services with application delivery - then the host doesn't need the applications installed, the self contained "TSVMS" houses everything.
Has anybody heard anything like this in any blogs from Citrix folks or Microsoft folks? I can only imagine this happening in a future rendition of Server 2008 and the next logical step would then be for Citrix to take advantage of it with XenServer etc etc. Imagine being able to have "TSCenter" where you can live migrate users from server to server and load balancing with a DRS equivalent software....
Interested to hear anybody elses thoughts on this. I'm sure I'm not the first to think about it....
I don't want to say this would not be useful (I think it would) but I also think it would be a bazooka to shoot a flight. A bazooka in terms of re-architecting how the products currently works.
After all you can achieve something very close to what you are describing with VDI. Sure you can't compare the "weight" of a VDI session (and it's OS) to the "weight" of a TS session in terms of resource usage but if you think about it (see the very first picture of this page that is what it is ..... each user session is in turn a selfcontained vm that you can move left and right as opposed to something very tight into a monolithic design such as that of the Terminal Services implementation).
Again I am not saying that what you depict is not important .... but perhaps the industry might find a slightly different way to do it .... perhaps it's not so elegant as you picture but it's much easier to achieve and support. As a matter of fact this is what's already happening.... Citrix now seems to have two very distinct branches which is desktop virtualization (i.e. XenDesktop) with which they are going to present the WHOLE desktop and Application virtualization (i.e. CPS) with which they are going to just present the applications. And these can be complimentary. I doubt Citrix will put too much efforts into the TS core technology when it comes to present the whole desktop. I am sure they are buying your idea and will be working on that ..... but in a VDI / XEN context leveraging existing technologies such as XenMotion etc etc.
My two cents.