Ant terminating immediately in Eclipse without any errors

Recently all ant builds started failing when started from within Eclipse without an apparent reason. When the ant target is invoked, the console briefly opens and closes again, without any message or error. /workspace/.metadata/.log finally reveals the cause: java.lang.NoClassDefFoundError: org/apache/tools/ant/BuildException Some Ant classes seem to be missing, strange. A look at Window -> Preferences -> … Continue reading Ant terminating immediately in Eclipse without any errors →

Speeding up Ubuntu 11.04 boot time

Just because I have nothing else to do on a lazy, rainy Sunday morning I thought it would be fun to see how much I can slash off the startup time for Ubuntu 11.04 64Bit on my HP Probook 4720s. The OS boots from a class 6 SD card (16 Mbyte/sec read) and 6 GB … Continue reading Speeding up Ubuntu 11.04 boot time →

Enabling the powerbutton in Ubuntu Server 10.04 on an AMD box

While shutdown –h does the trick of shutting down a server just fine, occasionally I’d prefer the haptic version. While I’ve never had problems getting the powerbutton to work with Ubuntu desktop versions, it didn’t work out of the box on my AMD Athlon XP. Fortunately the solution seems to be quite simple: sudo apt-get … Continue reading Enabling the powerbutton in Ubuntu Server 10.04 on an AMD box →

Varnish, session_linger and dropped connections

Recently I conducted a load test on my beloved low end Ubuntu 8.04 VPS. The setup consists of a mysql 5.1 DB, a Tomcat 6 webapp, openjdk 6 and Varnish 2.1.2. The load generator was issuing HTTP GET requests through a DSL connection which were supposed to create a decent load on Tomcat. To my … Continue reading Varnish, session_linger and dropped connections →

A counterintuitive relation between CPU and memory usage

Continuing my tests on low-end server environments, I recently set up a stress test of a load balanced tomcat webapp. Part of that tests consist in reducing the available memory for the webapp (JVM -Xmx switch) and see how low it could go before negatively affecting performance. It's common knowledge that once available memory runs … Continue reading A counterintuitive relation between CPU and memory usage →