Question 35: On AIX, free memory is near zero, how do I free more memory?
This is just how AIX works and is perfectly normal. All of memory will be soaked up with copies of filesystem blocks after a reasonable length of time and the free memory will be near zero. AIX will then use the lrud process to keep the free list at a reasonable level.
If you see the lrud process taking more than 30% of a CPU then you need to investigate and make memory parameter changes.