No discussion on software architecture would be complete without the mandatory argument over operating systems. System administrators and Oracle DBAs love to debate over which OS is ultimately better: UNIX or Windows NT/2000/XP. In fact, Democrats and Republicans often agree on more issues than UNIX and Windows bigots. Likewise, the Microsoft SQL Server versus Oracle debate is equally as heated. Be that as it may, there exists a relatively simple guideline for such selections: Let the size of the data warehouse be the deciding factor (see Table 2-1).
Without trying to evoke a huge argument, let me explain. Mid- to large-scale RISC-based UNIX/Linux platforms are currently much more scaleable than their Intel counterparts running either Windows or Linux. For example, Sun servers can hold up to 106 CPUs, while Intel-based solutions currently max out at 8. Plus, Sun servers can hold up to 60 GB of RAM, while Intel-based solutions max out at around 16. Of course, joint development ventures such as IA-64 between HP and Intel will only serve to blur these lines further, as the IA-64 architecture is expected to scale out to 2048 processors and run NT, Linux, HP-UX, AIX, and others.
The one possible Intel-based architecture that might work is Linux and OPS/RAC to build a multi-node, multi-CPU processing behemoth?a PC-based supercomputer of sorts. But this technology is still relatively new, so it is not something I can recommend based on detailed experience.
For now, very large data warehouses should be on Oracle 8i or 9i running on RISC-based UNIX/Linux.