Performance Audit Litany 2007
Here is the updated 2007 version of questions from the Computer Measurement Group (CMG) award winning Performance Audit Litany (PAL) paper. PAL provides a framework for beginning any performance study. The Performance Audit Litany 2007 starts with a blank slate and gathers its strength as it fills in answers to questions that form the foundation of the problem at hand. PAL is, in other words, the proverbial “good beginning.”
— Dutch proverb
It should only take you a few minutes to use this list of questions to launch your performance troubleshooting efforts on the right foot. When combined with T4 & Friends data showing the key system, network, storage, and business factors from the systems in question, you will find yourself in an excellent position to determine and then fix the cause of the slowdown.
Please note that it is perfectly OK if you don’t know the answer to a given question. Just jot down: “Don’t Know” or draw a dashed line. Surprisingly, you will find that the questions that cannot be answered right away often provide the most important clues as to what to do next.
If you would like some assistance in interpreting the answers you get or in how best to use the PAL answers in conjunction with T4, please contact us.
- What’s slow?
- How slow is it?
- How fast does it have to be?
- How important is each slow function?
- How much has this slowness already cost you?
- How much more will it cost you if you don't fix it soon?
- How much can you spend?
- When is it slowest?
- Is it ever fast (for example at some particular time of day)?
- Was it ever fast? If so, how recently and how fast was it?
- When did it first start to get slow?
- Did the slowdown happen all at once or has it slowed down more since then?
- Does the slowdown vary from day to day?
- Is the slowdown continuing to get worse?
- What significant events happened at the same time as the first recorded slowdown?
- What other significant events have happened since the first slowdown?
- Any hardware changes
- Any newer versions of software installed?
- Any changes to tuning parameters?
- Any new applications put into service?
- Any new users added to the system?
- Any new devices connected to the system?
- Any changes in disk fullness or fragmentation?
- Any new long-running (non-interactive) jobs?
- Any new systems accessing shared SAN storage
- How fast is the slow function, best case?
- What system resources (cpu, disk, memory, bandwidth) does the slow function consume when it runs?
- Is everything slow or are some functions OK?
- What’s the state and recent history of the key system resource factors?
- Any noticable changes in factors that correlate with the slowdown?
- Any changes that correlate with resources used by the slow function?
If you have access to T4 & Friends data, you will find it particularly helpful in answering many of these questions in more detail. The PAL answers will help point you to the most useful periods of time and the T4 data will make it easier for you to see what processes were at work during those periods.