I have analyzed the LINUXP01 memory usage over last week. I noticed that
between the hours of 04:00 ? 04:30 AM every morning is when the largest
swap increase occurs. 04:15 AM is when some Linux housekeeping starts.
These tasks complete in about 3-5 minutes. These tasks require memory and
Linux will swap out memory not being used. The memory that is being
swapped out is from WebSphere. This is normal Linux process. What is
interesting is that this memory is never swapped back in. As the first
graph depicts, we see a jump in swap space usage every morning during the
housekeeping process. Every day shows another increase in swap space
utilization and a corresponding decrease in WebSphere resident memory size
about the same time as shown in the second graph.
This raises the following questions:
Since the major portion of the swap space utilization is never brought
back in, it is obviously not needed. Is this indicative of too much Java
heap size which never forces garbage collection? Is there a ?memory creep?
condition in WebSphere, WebSphere?s JAVA, or one of the applications
running under WebSphere? Are the trees blocking my view of the forrest?
What can I conclude from this? All comments and suggestions are welcome.
The Linux guest size is 768 meg and the Java heap size is min 50 and 700
max.
Peter
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