When anticipated correctly, upgrades are relatively straightforward. Hewlett-Packard, for example, is touting the advantage of parallel server technology over more traditional MPP architectures. There are multiple sources. All major hardware vendors have a multiprocessor product line, so you can shop around and count on continued competition, variety and innovation among major systems. Choosing SMP, clustering or MPP should depend upon your specific applications and goals.
Solutions change almost as fast as definitions.
It used to be that data warehousing, which must store large volumes of data and provide reasonable response times on queries for a large number of users, was an application for MPP architectures. Now, SMP solutions and clusters should be considered, too. SMP is sure to become more popular as more tools and applications are developed for these environments. And clusters do not necessarily require new hardware, while MPP systems usually do. It is best to have an experienced, vendor-neutral guide when going through this the first time.