VDI 1.0 has poor reliability & availability
In VDI 1.0, all the intelligence was built into the data center. The clients were “dumb”. They had to ask the data center for instructions on almost everything. This resulted in multiple round trips with tens of handshakes for a user to get a simple connection to an application or a desktop.
A typical VDI 1.0 deployment contains multiple components deployed in highly available pairs — SQL Servers, Load Balancers, Portals, Brokers, Licensing Servers, Provisioning Servers, etc. Multiple components are involved in every single user request, sometimes multiple times. It takes 33 steps to fulfill a login request, as described by a Citrix engineer. Through the power of compounding, even if each of the steps are 99% reliable, the overall sequence is now only 71.77% reliable (0.99^33 = 0.7177). That’s only if everything works. If something does go wrong and a user is unable to login, how do you figure out which one of those 33 steps failed?