If there's insufficient space in device, data will not be saved, and online players will not receive any message. After about 2 hours, the server will crushed. After restart it, players will find all the changes they made (buildings, materials and etc.) disappeared!

Plugins like CoreProtect doesn't work in this situation, because of insufficient space, they can not submit database transactions.

In order to protect players' works, it's necessary to close server immediately when there's no space left on device. That is what Non Enough Space Server Closer do.