AIX 5L Problem Determination - IBM Redbooks

2.1 Defining the problem
The first step in problem resolution is to define the problem. It is important that
the person trying to solve the problem understands exactly what the users of the
system perceive the problem to be. A clear definition of the problem is useful in
two ways:
► It can give you a hint as to the cause of the problem.
► It is much easier to demonstrate to the users that the problem has been
solved if you know how the problem is seen from their point of view.
For example, consider the situation where a user is unable to print a document.
The problem may be due to the /var file system running out of space. The person
solving the problem may fix this and demonstrate that the problem has been
fixed by using the df command to show that the /var file system is no longer full.
This example can also be used to illustrate another difficulty with problem
determination. Problems can be hidden by other problems. When you fix the
most visible problem, another one may come to light. The problems that are
unearthed during the problem determination process may be related to the one
that was initially reported. In other words, there may be multiple problems with
the same symptoms. In some cases, you may discover problems that are
completely unrelated to the one that was initially reported.
In the previous printing example, simply increasing the amount of free space in
the /var file system may not solve the problem being experienced by the user.
The printing problem may turn out to be a cable problem, a problem with the
printer, or perhaps a failure of the lpd daemon. This is why understanding the
problem from the user’s perspective is so important. In this example, a better
way of proving that the problem has been resolved is to get the user to
successfully print her document.
2.2 Collecting information from the user
The best way of understanding the problem from the users’ perspective is to ask
questions. From their perception of the situation, you can deduce if they have a
problem, and the time scale in which they expect it to be resolved. Their
expectations may extend beyond the scope of the machine or the application it is
running.
8 IBM ^ Certification Study Guide - AIX 5L Problem Determination Tools and Techniques