IT Reliability through Business Transaction Management

...Continued from the last post

Enabling Reliable IT – Managing Performance

How do you know when an end user is experiencing bad response times?

• They call into the help desk to complain – usually only after a number of past events where they were un-happy with the application’s reliability.
• An end user monitoring tool measures bad response times

End User Measurements

There are a great number of tools on the market today that perform this task in a variety of ways, below is a summary of the different approaches.

Software Based Real User Measurements

Desktop Agent

• Strength – enables the monitoring of the end user’s desktop and can measure response times for fat client based applications
• Weakness – must be installed at each desktop

Javascript Injection

• Strength – no need for end user installation
• Weakness – Javascript needs to be added to web application code

Browser Plug-In

• Strength – easy installation without code modification
• Weakness – still requires end user installation

Network Appliance Based Real User Measurements

All of these solutions utilize a network sniffer installed at a port mirror in order to guess end user response times. The advantage of using this solution is the ease of installation; the disadvantage is the cost of putting these probes at all of the points where the network is accessed and the

accuracy of the data.

Synthetic End User Measurements Performed by “Robots”

The classic availability monitors use this approach - scripts are used to “ping” the system and check its availability. The advantage is that availability can be monitored overnight and before the morning workload, the disadvantage is that real user response times are not being measured and scripts have to be modified with every change of the application.

Finding the Location of the Problem

Now that you know that there is a problem - since the end user is experiencing reliability issues with an application, narrowing down the location of the problem is the next step. Research has shown that 80% of time spent on troubleshooting performance problems is spent on finding the actual location of the problem.

In the picture below “John the User” is experiencing poor response times – the IT department is tasked with resolving this issue.

To be continued next week...