Having an issue that no one seems to be able to find an answer to.
I'm trying to setup a new McMyAdmin server... version right now is 1.11, running Vanilla with no plugins, mods, Spigot, Bukkit, etc. Straight, out-of-the-box, Minecraft.
The server is an OpenVZ VPS running Ubuntu 14.04 x64. It has 8GB of RAM total, and 4 cores for the processor. Should be pwerful enough for a Minecraft server expected to hold maybe around 10 clients at most, right?
Since the initial server startup, it's been spamming "Can't keep up! Did the system time change, or is the server overloaded?" at various intervals, even with no one on the server. The time it's running behind can vary anywhere from half a second to 15 seconds. It also started throwing issues saying "[PlayerName] moved too quickly!" and giving that player the rubber-band effect. The server is currently running Java8 in "server" mode. The memory assigned to it is 3GB... according to McMyAdmin's panel, it hasn't peaked above 1GB yet.
The server is shutting down at random and auto-restarting, with no message in the MC log files or on the console other than "Server stopped unexpectedly." This typically happens 20 seconds or so after the "Can't keep up" errors, but it does not occur after every "Can't keep up error."
Watching the server in nmon at first showed no issues with CPU or RAM Usage. McMyAdmin, like I said, showed the levels to be stable as well. Spigot IRC and me wrote it off to being an issue with Disk IO, so I filed a ticket with my host... who came back saying that there were no IO problems that they saw. So, I watched nmon again... and noticed that at any given point, one core would be spiking to near 100% usage from "User." Most of the crashes seemed to occur during these spikes. So it looks like the issue is CPU... but I can't figure out why. All the performance configuration settings, barring RAM Allocation for Java and the setting to "server" for the Java mode are set to default. I don't think that it's garbage collection, since it's not even using a gig of its allocated RAM when these unexpected shutdowns occur. Does anyone have any other potential ideas or hints? And yes, I tried apt-get upgrade and a reboot as well.
E: Sorry about the messed up code display. I'll try putting it into a Pastebin.
E: Fixed. Here's the console log: http://pastebin.com/A6kvat6j