Let's examine each phase, starting with Collecting.
Figure 10.1 The performance tuning cycle The Collecting phase is the starting point of any tuning exercise.
The business perspective The business perspective also plays a significant role in performance management.In this context, someone has to do determine how much hardware is required, how to make provisions for peak loads, how to balance out spikes with low overall load, and how to determine or satisfy service-level agreements.It's really a matter of perspective; users and administrators simply have slightly different ways of viewing system goals and interpreting performance.For most users, performance equates to speed—the response time of the system they're using.It's often necessary to make price and performance trade-offs—it may be too expensive to have enough servers for maintaining low processor utilization at all times, so low average utilization with spikes becomes acceptable.
Performance tuning is the main activity associated with performance management.
When they activate a hyperlink and the requested page is retrieved and displayed quickly—typically in less than 10 seconds—their perception of performance is favorable.
(It's interesting to note that it's not uncommon for a user to think that a page takes longer to retrieve and display than it actually does.) From a user's perspective, the definition of performance and the primary goal of performance tuning is the same—make it fast.
Regardless of what part of the system you're tuning, you require a baseline against which to measure performance changes.
You need establish a pattern of system behavior when the system is idling as well as when specific tasks are executed (for example, adding a member to the cluster and synchronizing it to the controller).
During this phase you're simply gathering data with the collection of performance counters that you've chosen for a specific part of the system.