(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
when going live. So let’s look at the different JVMs, what makes them
unique and how to ensure that Garbage Collection is running smooth.
The Garbage Collection ergonomics of the Sun Hotspot JVM
Everybody believes to know how Garbage Collection works in the Sun Hotspot
JVM, but lets take a c... (more)
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 ea... (more)
Over the last couple of months I have been talking to more and more customers
who are either bringing their Hadoop clusters into production or have already
done so and are now getting serious about operations. This leads to some
interesting discussions about how to monitor Hadoop properly and one thing
pops up quite often: Do they need anything beyond Ganglia? If yes, what
should they do beyond it?
As in every other system, monitoring in a Hadoop environment starts with the
basics: System Metrics - CPU, Disk, Memory you know the drill. Of special
importance in a Hadoo... (more)
In a recent article we have shown how the Java Garbage Collection MXBean
Counters have changed for the Concurrent Mark-and-Sweep Collector. It now
reports all GC runs instead of just major collections. That prompted me to
think about what a major GC actually is or what it should be. It is actually
quite hard to find any definition of major and minor GCs. This well-known
Java Memory Management Whitepaper only mentions in passing that a full
collection is sometimes referred to as major collection.
One of the more popular definitions is that a major GC is a stop-the-w... (more)
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)