> Does it sound like apache2 was using up all the memory? If so, should > I look further for a catalyst or did this likely happen slowly? What > can I do to prevent it from happening again? Should I switch apache2 > from prefork to threads?
Do you need the full 256 instances? How many simultaneous connections do you have? Are you running keep alive (connection persistence, and i *think* it also implies connection pipelining). Its the default these days but if you're been upgrading through older versions the config might have it disabled. Also, WRT swap you can set vm.swappiness in /etc/sysctl.conf from the default of 60 to something lower, to reduce the propensity to use swap.
