Possible Duplicate:
Why does Red Hat Linux report less free memory on the system than is actually available?

after freshly rebooting the VM "top" indicates about 0.5 GB out of 8 GB RAM are being used. Then we run some installation code. After the install program is done and all subprocesses are terminated, "top" still shows around 5 GB being used, e.g.

Mem: 8062088k total, 5021456k used, 3040632k free, 187892k buffers

Later on, when running the installed software we run into OutOfMemoryErrors even for small Java programs being started. This behaviour did not really change/become better when upgrading the VM from 4 GB to 6 GB and to 8 GB.

Is there a way / a tool

  • to find out what is this memory being used for?
  • to find out how can the memory be released?
  • how can that memory usage probably for operating system usage (rather than user processes) be limited?

Many thanks for any hint, Uli


Are you running out of Tomcat? I believe most Java containers will have a memory setting, and AFAIK tomcat's starts at 128 megs, usually you have to increase that.

Not the answer you're looking for? Browse other questions tagged or ask your own question.