I wager the guess that you are using linux? (Edit: Dumb me. Of course it is or why should it be under "Support: Linux Servers"
Are you certain that you didnt change a thing. Maybe updating the OS?
What distro/kernel do you use?
Having no swap at all is not very advisable but it probably wont help much if you are out of RAM because your server might be slowing to a crawl when swapping to harddrive.
Please have a look in /etc/fstab and see what partition is the swap partition. In case the server is running on one disk or has an hardware raid you should make sure that that partition has the correct system ID (82) and is set up as a swap partition (mkswap /dev/<whatever>) If that is the case do a swapon -a, maybe you have a wrong fstab entry. If you have a software raid the (raided)swap partition should have a system id of 'FD' or it wont work propperly.
See if any shared memory segments are still in use ... as much as I hate the idea(typical Windows procedure, if it wont work reboot and try again) you should think about rebooting the server. Depending on the kernel you use there are some strange bugs. Eg. after 400+ days of uptime under older 2.4.ish kernels ect.
Threaded Mode
