I'm finding that my server doesn't like to reboot gracefully. Either selecting "graceful server reboot" in WHM or actually typing "reboot" in SSH, which then tells me the server is shutting down. My server is then incommunicato indefinitely until I actually do a hard reset remotely.
Is this common? Is there some way to find out why this is happening ?
The best option is having console checked after you type in reboot to see where it hangs. I've seen some Centos systems hand on restarting system on the stock kernels (3 and 4, but haven't seen it in 5).