Extreme Server Lag

[Cosmology27]

So I've had a server up a little over two months now. I only have like 6 of us in there, and it's been running super smooth. The other day the server started saying that "can't keep up" message excessively, way more than usual. I did a full restart, and it immediately started saying it couldn't keep up. This is right after I restarted my computer, no programs are open other than the server, and no one was in the server. I left it for a while, people joined, complained about lag. Did another full restart, still lagging. I checked all the spawners and machines, nothing is out of the ordinary.
I'm just wondering if anyone has any advice as to how I can fix this. It's not crashing so there's no crash reports, it's just running really really laggy.
Thanks for the help

 

[TheDJParadox]

Have you tried Tick Threading, You should give that a go, it helped me a lot with my server. If that doesn't work for you then that is something to do with the world from what I can guess..?

 

[Cosmology27]

Fantastic I'll try that, where can I find instructions on how to do that? (I'm new to the server realm).
Thanks!

 

[DZCreeper]

https://github.com/nallar/TickThreading/blob/master/INSTALL.md

Here you go.

Disclaimer: This mod could be considered in alpha or beta stage. This means not all default settings may be what you need or want, and it can be unstable. Make regular backups if you decide to use it, and if you find any bugs, make a report on Github so the author can fix them, he does so ASAP when he learns a bug exists.