What is problem determination

greasyservantInternet and Web Development

Jul 30, 2012 (5 years and 9 months ago)


What is problem determination?

Problem determination includes debugging applications, but also diagnosing the system
at large by investigating product configurations and verifying the means by which all of
the system’s components interact.

The problem d
etermination process

Unable to start a component

Hanging component

Crashing component

Misbehaving component

The above problems may be due to one or more of the following.


Lack of resources

Programming error, such as

Memory leak

Dead lock


Product defect

The problem determination process


Identifying the problem
and able to recreate it at will

Step 2:

(by reducing the complexity and using different scenarios)

Step 3:

Collect logs
, read

and correlate them.

Step 4:

Isolate the offending component

Step 5:

Fix the problem
Product defects are fixed thru e

Key points for websphere problem determination



Understand how the software works under the covers, how messa
ges are passed from one
component to another, and how one component interacts with another component.

Be careful about assumptions. Only report and log what you can verify.

What is different today from yesterday? (Look at those change logs).

Can you repr
oduce the problem? If so, it will be much easier to solve.

Does this problem affect only this user or this workstation? This helps determine where
to look

Describe the symptoms of the problem in detail with precise descriptions. Ambiguity will
cause ser
ious problems later.

If there are multiple problems, try to separate them and deal with them independently.

Find the possible causes for the symptoms.

When testing, limit the number of changes made before a test (do not change many
parameters at once).

Keep a log of symptoms, messages, files, tests, results from tests, and conclusions.

Retrace the steps described to recreate the problem and see the results yourself.

Understand the meaning behind the request that has created or induced the problem, this
will help you isolate the problem.

Use a controlled test environment when possible.

Find out what is NOT part of the problem. This will help you eliminate variables in an
already complex equation.

Follow the problem determination method.

Download the l
atest symptoms database, reproduce the problem, and run Log Analyzer
over your activity.log file. This will allow you to check for known errors much more
efficiently and effectively because Log Analyzer has a symptoms database which
matches known problems
to your current websphere problem as noted by the activity.log.
Resolutions based on the problems are available with the symptom database, which might
entail the next step after running Log Analyzer

checking the e
fix website.

Check the e
fix website

Key points to remember about WAS5.0

Notes on test and production environments

Things to have when working a problem

Websphere problem determination and isolation

Introduction to WAS 5.0

Admin server

Application server

Http server and websp
here http server plug

Embedded http server

Application code running in the web container and EJB container

Basic problem determination for configuration and administration

Installation problems

Starting the websphere admin server

Starting the w
ebsphere admin console

Starting wsadmin in interactive mode

Running XML Config

Start the application server

Basic problem determination for HTTP requests

JVM crashes and hangs

Admin server crashes and hangs

App server crashes and hangs

Memory lea

Application heap leaks

Native heap leaks

Websphere session affinity

Servlet workload management

EJB workload management

The HTTP server plug

Understanding the plug

The plugin
cfg.xml file

Expected behavior of the plug

ubleshooting the plug

The http server will not start

Native.log contains entries about the configuration errors

Changes were made to the plug
in configuration, but plug
in behavior has not

Browser clients cannot reach web application

nternal Server Error” message in browser (a.k.a HTTP error 500)

“404 File Not Found” message in browser

The plug
in is not communicating with the application server

Requests are not distributed to all clones

Session affinity problems

in logs and


The plug
in log file

Tracing the plug

Reading plug
in logs and traces

Web server log files

in problem determination examples

“404 file not found” error scenario

Improper workload management scenario

erences between V4.0 and V5.0

Memory leaks

Tivoli performance monitoring

How to deploy an application

What factors are considered in clustering?

What parameters are used in tuning?

Adv of vertical and horizontal scaling

Deploy an EJB

How is security ac

Performance tools

JMS security enable

Tuning parameter with respect Solaris

When or under what conditions your app server freeze.