2.3. Performance management

Performance management is the activity in an installation that monitors and allocates data processing resources to transactions according to a service level agreement (SLA).

There are three main ways to solve performance problems:

  • Buy: You can simply buy more resources.

  • Tune: Tuning your system makes more effective and efficient use of those resources.

  • Steal: You can “steal” the resources from a less critical transaction.

2.3.1. I/O performance

As CPU speed increases, the I/O response time (I/O Tr) is the determinant factor in the average transaction response time, as shown in the formula:

I/O Tr = I/O Ts + I/O Tw

So obviously, you can get excellent response time returns by reducing I/O wait time and I/O service time. ...

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