Command Line Arguments in Python

When I need a new tool, I often code it in Python. Often, command-line options are useful. Sometimes it is possible to have a fixed set of parameters, but this is not very flexible. Fortunately, Python has standard libraries to handle parsing command lines. Three libraries provide varying capabilities. Some of the systems I run on have […]

Tuning Linux CPU Performance

A recent kernel change broke my CPU performance tuning. I have an AMD processor that presents 4 cores to the kernel. The process in this article should work for Intel processors although the governors and CPU settings tree may be different. Different kernels may also have different settings. The current kernel allows setting the governor per […]

Disabling SSLv3 to block Poodle

The new Poodle vulnerability lead me to disable SSLv3 on my Ubuntu server. I have TLS/SSL enabled on three services: apache2, exim4, and dovecot2. Each service required a different method to disable SSLv3. While SSLv3 is mostly history, the techniques I used can be applied to other TLS versions. Ubuntu uses configuration files split into […]

Disable TraceClassUnloading in Java 6

I recently discovered logs filling up with log messages for classes being unloaded during garbage collection. After a little research, I found that the TraceClassUnloading switch gets turned on by the Xloggc switch. After a little testing, I found that this can be resolved by adding the argument -XX:-TraceClassUnloading after the -Xloggc argument.