Scalability and high availability has been one of the painful realisation for one of my customer. Three months after go-live they starts to find performance issues and the solution struggling to process large number of business transactions. Amongst the 41-page recommendation report, as a tactical (short-term) resolution I recommended the customer to go with virtual scaling pattern to ease their immediate pain.
Figure source: The Different Paths to Virtualization, Issue 24, The Architecture Journal
