Just wanted to give my experience with installing FMS 14v3 (but probably exists with all FMS versions) on OS X this weekend.
It's very important to install the Java 6 package for OS X from Apple from here: Java for OS X 2015-001
This is in addition to the Java 8 package from Oracle, because for reasons known only to the Keystone Kops at Oracle (perhaps only rivaled by the Keystone Kops in charge of the SSL portion of FMS), even after three major versions since Oracle took over maintenance of Java from Apple, they still don't ship some of the necessary dev frameworks with their Java 8 package, so the old Apple package is necessary for many deployments. Java 6 is not actually used; it just installs those needed frameworks.
OS X normally prompts the user whenever it needs that Java 6 package to be installed, but FMS is not triggering that prompt, so it's a difficult problem to detect.
How this affected my FMS 14 server is that without the Java 6 package installed, whenever a remote client opened a database that triggered the issue (by requiring Java for whatever reason), the fmserverd process would start chewing up lots of CPU, eventually go deaf (File/Open Remote on a client showed "No Connection"), then degrade until the fmserverd process crashed. I've attached the crash log for anyone that wants to reference it.
How I got the clue was that I opened one of the affected databases locally from the server machine using the FM client installed on the actual server box (with the server offline) and that triggered the Java 6 prompt from OS X. After I installed the Java 6 package on the server, the crashes stopped.
YMMV, but I had tried pretty much everything before that (uninstall/reinstall of FMS, all the usual OS and disk checks/troubleshooting, etc), and the crash was reproducible and disappeared immediately after I installed the Java 6 package, so I'm pretty confident that was the fix.