When discussing Oracle performance challenges with DBAs and consultants over a period of years, a common trend became evident (especially in data warehousing). A lot of time was spent in figuring out where indexing might apply and where other database tuning methods might be used. However, little time was spent in understanding the underlying hardware and whether it was "balanced". The flexibility Oracle provides choice of hardware configurations that can actually result in unusual server and storage combinations that are not optimal. That became increasingly evident as we took another look at configurations that had been deployed in companies and organizations.
To illustrate this, let's imagine a server configuration that consists of 8 CPU cores with each core delivering throughput of 200 MB/second for a total of 1600 MB/second. Given that throughput, the number of 1/2 Gigabit HBAs and disk controllers each delivering 200 MB/second of throughput in the hardware configuration should also total 8. The number of disk spindles each delivering 50 MB/second of throughput should total 32. Other components you might consider providing throughput include switch and interconnect technologies.
Often, we come across configurations that have a fraction of the HBAs and disk spindles needed for balance. Tell-tale signs of such a configuration include CPUs that are always operating at a small percentage of capacity, even while I/O is consistently at or near 100 percent utilization. Enterprise Manager can point out these statistics. Many organizations struggle getting this balance right since they negotiate with one vendor or sales team for storage, and another for the server configuration. You should not assume anyone understands the need for balance other than yourself.
If this sounds familiar, often the easiest solution in many organizations is to simply add more HBAs and doublecheck whether your disk drives can deliver the right performance (e.g. there are enough spindles provided). These seem to be the most common missing ingredients and are also usually an inexpensive fix. Oracle's Optimized Warehouse Initiative (OWI) is designed to help provide configuration guidance for organizations deploying new servers from Dell, HP, IBM, SGI, and Sun.
One interesting proof point we see are some of the "competitive" proof of concepts and benchmarks we become involved in against vendors who provide both hardware and software in fixed or "appliance" configurations. Since these vendors mandate certain hardware configurations consisting of servers and storage, their configurations are balanced. Since Oracle began leveraging the OWI configurations for balanced recommendations, we have seen similar or better performance in our comparative benchmarks with similar minimal tuning.
Some of our early Oracle Essentials readers provided feedback that they doubted whether a discussion of hardware platforms was relevant in this book. What has become evident to us over the past 3-4 years is that this is particularly relevant to successful deployment and simplified tuning of the Oracle database.