In the Cloud, you have to trust your instruments...

Michael Kopp

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Top Stories by Michael Kopp

Anyone who ever monitored or analyzed an application uses or has used averages. They are simple to understand and calculate. We tend to ignore just how wrong the picture is that averages paint of the world. To emphasis the point let me give you a real-world example outside of the performance space that I read recently in a newspaper. The article was explaining that the average salary in a certain region in Europe was 1900 Euro's (to be clear this would be quite good in that region!). However when looking closer they found out that the majority, namely 9 out of 10 people, only earned around 1000 Euros and one would earn 10.000 (I over simplified this of course, but you get the idea). If you do the math you will see that the average of this is indeed 1900, but we can all agree that this does not represent the "average" salary as we would use the word in day to day li... (more)

How to Identify a MongoDB Performance Anti Pattern in Five Minutes

The other day I was looking at a web application that was using MongoDB as its central database. We were analyzing the application for potential performance problems and inside five minutes I detected what I must consider to be a MongoDB anti pattern and had a 40% impact on response time. The funny thing: It was a Java best practice that triggered it. Analyzing the Application The first thing I always do is look at the topology of an application to get a feel for it. Overall Transaction Flow of the Application As we see it's a modestly complex web application and it's using Mongo... (more)

Application Performance Monitoring in Production

Setting up Application Performance Monitoring is a big task, but like everything else it can be broken down into simple steps. You have to know what you want to achieve and subsequently where to start. So let’s start at the beginning and take a top-down approach Know What You Want The first thing to do is to be clear of what we want when monitoring the application. Let’s face it: we “do not want to” ensure CPU utilization to be below 90 percent or a network latency of under one millisecond. We are also not really interested in garbage collection activity or whether the database ... (more)

Application Performance Monitoring in Production

Last time I explained logical and organizational prerequisites to a successful production level application performance monitoring. I originally wanted to look at the concrete metrics we need on every tier, but was asked how you can correlate data in a distributed environment, so this will be the first thing that we look into. So let’s take a look at the technical prerequisites of successful production monitoring. Collecting data from distributed environment The first problem that we have is the distributed nature of most applications. In order to isolate response time problems or... (more)

How Garbage Collection Differs in the Three Big JVMs

(Note: If you’re interested in WebSphere in a production environment, check out Michael's upcoming webinar with The Bon-Ton Stores) Most articles about Garbage Collection ignore the fact that the Sun Hotspot JVM is not the only game in town. In fact whenever you have to work with either IBM WebSphere or Oracle WebLogic you will run on a different runtime. While the concept of Garbage Collection is the same, the implementation is not and neither are the default settings or how to tune it. This often leads to unexpected problems when running the first load tests or in the worst case... (more)