The above top output is ok and memory is not exhausetd. I guess we are chasing a phantom here as what you thought is exhausetd memory is just the normal way the linux kernel works to speed up the system. The linux kernel uses memory to cahche the filesystem, so no free memory is not a bad sign in any way.
According to top, your server is not overloaded. Its nearly sleeping because it has nothing to do.
Last edited by till; 3rd March 2011 at 02:03.