Getting alerts when Java processes crash
When bugs occur in the Java runtime environment, most administrators want to get notified so they can take corrective action. These actions can range from restarting a Java process, collecting postmortem data or calling in application support personnel to debug the situation further. The Java runtime has a number of useful options that can be used for this purpose. The first option is "-XX:OnOutOfMemoryError", which allows a command to be run when the runtime environment incurs an out of memory condition…
$ read more →Monitoring Java garbage collection with jstat
Java memory management revolves around the garbage collector, which is the entity responsible for traversing the heap and freeing space that is being taken up by unreferenced objects. Garbage collection makes life easier for Java programmers, since it frees them from having to explicitly manage memory resources (this isn't 100% true, but close enough). In the Java runtime environment, there are two types of collections that can occur. The first type of collection is referred to as minor collection…
$ read more →Building 32-bit openssl libraries with the Sun C compiler
This week I needed to install OpenSSL 0.9.8g on one of my servers. When I went to configure and build the libraries with the Sun C compiler, I noticed that 64-bit libraries were produced by default. It turns out that this is the default behavior if you try to build OpenSSL on a 64-bit platform. To build 32-bit shared libraries, I ran Configure with the "shared" and "solaris-x86-cc" options: There may be other ways to do this, but this method appears to work ok.
$ read more →Monitoring the IPMI system event log
If you have a relatively recent server, your machine most likely supports IPMI. One technology that makes IPMI extremely useful is the baseboard management controller (BMC), which is an out-of-band controller that monitors the health of your server platform. Health monitoring is accomplished by distributing sensors throughout the server, and feeding the data these sensors collect back to the BMC. If the BMC detects a fault condition, it can log an error to the system event log…
$ read more →Finding bugs in Java programs
A while back I came across findbugs, which is a static analysis tool that can be used to locate bugs in Java programs. Findbugs is able to identify a number of bug patterns, which range from bad practices to performance and multithreaded programming bugs. Findbugs can be invoked through a graphical utility, or by running the findbugs command line utility. The command line option has the advantage that it can be easily incorporated into existing build processes (there are options readily available to integrate findbugs with maven and ant), allowing code to be tested when new builds are created…
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