I would like to point you to two articles in the latest Northern California Oracle Users Group (NoCOUG) Journal here.
The first is an interview of Kevin Closson here. The interview is long and will take some time to get through… so set aside 30 minutes… it will be worth it as Kevin discusses Exadata, shared-nothingness, and other topics related to database hardware architecture.
The second article I would like to suggest (by the way there are several other excellent articles) is by Dr. Bert Scalzo. He reminds us that our job as engineers is to build the most cost-effective solution… not to build the perfect solution. He suggests that hardware should be treated as a dynamic resource that can be provisioned easily to solve performance problems.
I have argued that in a shared-nothing, scalable, architecture it is often cheaper to add another $20,000 fat server than to spend $100,000 of staff time to tune around a performance problem. This is especially true when the tuning involves building indexes and materialized views or pre-aggregated tables that make your warehouse fragile and more difficult to tune the next time. See here…
Back to Kevin’s interview and to tie the two articles together… Kevin suggests that as long as data flows into the CPUs fast enough then there is no reason to pick a shared-nothing architecture over a shared-everything architecture. He insists on symmetry and rightfully points out that a shared-everything system can be symmetrical. But it is more difficult to maintain symmetry as you scale up a shared-everything system… and easy scale is what is required to treat hardware as a dynamic resource. So… I remain convinced that shared-nothing is the way to go…