The server that runs the simulators has been upgraded to run OS X 10.10.1 and OS X Server 4.0.
First impression is that the upgrade went well with one exception; OpenSim and specifically the http server in Robust now has significantly more open files during startup, so it crashed with too many open files messages.
This can be fixed by logging out the user that runs the OpenSim server and from a privileged account issue the terminal command
sudo launchctl limit maxfiles 4096 65536
This will increase the allowed open files per process to 4096 with the higher number being the allowed open files per system. Alternatively one can do the same with ulimit -n command from a privileged account.
After raising the limit and logging the user that runs OpenSim back in, both Robust and OpenSim started and runs without problems. Memory and CPU seems to be the same as before the upgrade.