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IN THIS CHAPTER
The first part of any DB2 performance management strategy should be to provide a comprehensive approach to the monitoring of the DB2 subsystems operating at your shop. This approach involves monitoring not only the threads accessing DB2, but also the DB2 address spaces. You can accomplish this task in three ways:
I will examine these monitoring methods later in this chapter, but first I will outline some performance monitoring basics. When you're implementing a performance monitoring methodology, keep these basic caveats in mind:
NOTE Tuning goals should be set using the discipline of service level management (SLM) . A service level is a measure of operational behavior. SLM ensures applications behave accordingly by applying resources to those applications based on their importance to the organization. Depending on the needs of the organization, SLM can focus on availability, performance, or both. In terms of availability, the service level can be defined as "99.95% up time, during the hours of 9:00 AM to 10:00 PM on weekdays." Of course, a service level can be more specific, stating "average response time for transactions will be two seconds or less for workloads of 500 or fewer users." For a service level agreement (SLA) to be successful, all of the parties involved must agree upon stated objectives for availability and performance. The end users must be satisfied with the performance of their applications, and the DBAs and technicians must be content with their ability to manage the system to the objectives. Compromise is essential to reach a useful SLA. If you do not identify service levels for each transaction, then you will always be managing to an unidentified requirement. Without a predefined and agreed upon SLA, how will the DBA and the end users know whether an application is performing adequately? Without SLAs, business users and DBAs might have different expectations, resulting in unsatisfied business executives and frustrated DBAs. Not a good situation. |
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