I don't flat out say that there is a memory bottleneck. I always say that it looks like Oracle is consuming a lot of memory, a point an administrator will never argue. I'll ask if the administrator feels there is a lot of memory pressure being placed on the system-perhaps even too much for the current memory capacity. When I put the situation in those terms, a very productive memory-related discussion occurs.

Like it or not, Oracle DBAs are losing control of the IO subsystem. Modern-day IO subsystems are so complex that they frequently require a full-time administrator. Adding to our problems, IO vendors in particular can be very abusive and just plain uncooperative with DBAs. But while the configuration and operating of the IO subsystem may be out of our control, we can very easily tell if the IO subsystem is not providing the capacity the Oracle system needs. In this section, I will describe how to diagnose the IO subsystem and suggest how to handle aggressive vendors.

Before we dive into the technical details, let's consider a nontechnical solution. I still find that most IO problems can be resolved by balancing the IO workload. This may sound simplistic, but while volume management software does a fantastic job balancing IO within its realm, and RAID arrays do much of the same, when multiple realms exist, they may not be balanced. Let me explain this by telling a story.