I was helping out a member of my CFUG with some questions about the JVM, and I wanted to point him to a way to see how big his PermGen is at runtime.

Last week I wrote a Server Memory monitoring tool using Flash Remoting. I'm not much of a flash developer, but it only took a few hours. Here's a screen shot of the tool:

Keep in mind this tool only shows the memory for the JVM instance that ColdFusion MX is running in.

Macromedia's Recent Technote: Maximum JVM heap size greater than 1.8GB will prevent ColdFusion MX from starting points out the limitations of a the JVM on a 32 bit architecture.

Wondering where the number 1.8GB comes from? Moazam Raja's recent blog entry explains.

Here are some code to find out some info about the memory usage of CFMX or BlueDragon. The Java API provides three methods in the java.lang.Runtime class: freeMemory, totalMemory, and maxMemory.