The changes to capacity management can be largely grouped into two areas:
Operationally, virtualization changes the IT infrastructure team from system builder to service provider. The application team no longer own the physical infrastructure, and it is now a shared infrastructure. This creates a two-tier capacity management:
At the VM level, capacity management is done by the application team. They determine the size of their VM, and then buy the capacity from the infrastructure team. They need to adjust the size, as oversizing leads to performance issues.
At the physical infrastructure level, the infrastructure team must perform capacity management as a single team. The joint team must take care of computing, networking, storage, and DR. The mindset has to change from that of a system builder to a service provider.
Architecturally, the infrastructure moves from a bespoke system to standardized hardware. The application team no longer need to dictate the specifications...