Dear amadin,
I can not help you with your request, but maybe you want to over think the how you ask questions.
Here is an short essay¹, which explains how your questions is going to interpreted by other people.
Do not get my wrong. It is OK, to ask for support, but in the end the online reason, why people answering questions, resolving problems is because they want the community to grow².
In the first place, the fact that your server does not work, has nothing to do with minetest.
In the second place, linux can not handle "fall down" nicely(assuming you mean hardware problems) an is unforgiving when this happens a lot.
In the third place, a application only hardly can handle something which the OS is not able to.
Since I know nothing about your problems, you have many, many options.
Forget setting up a minetest server, when you can not get your machine running smoothly!
Since it is by know means the responsibility of the minetest community to fix your server, here are 3 options:
1. Talk to your local/remote administrator
2. Read the essay and then ask in the irc of your linux distro, if they can help you fix this behaviour.
3. If and only if it is an crash of the minetest server, while the machine runs fluidly write a post. Where you name the mods you use, post all relevant log files and post a text when and how the minetest server crashes(the keyword is "being able to reproduce the error in a controlled environment")
I do not play cop nor admin. I try to give you a feedback, which you can learn from, as direct as possible.
Also in your post you did not mention anything about ssh. When it is not important, leave it out from the subject.
If you want to communicate to us that you have no physical access to the server please state so.
If thats the case you can also talk with the tech support of your hoster(i assume it is an commercial one).
Please have a nice time, when not tech support is available from your hoster, talk with the community of your distro.
If you do not know what distro you are using. You should get more familiar with your system and the community before you handle the burden of being the admin of a server. In this case you`ve been warned.
PS: When you want to find out your distro, you can google, how you do this.____________________
1 Guide to teach how to ask technical questions in a way more likely to get a satisfactory answer :
http://www.catb.org/~esr/faqs/smart-questions.html2 vague over generalisation, individual motives vary a lot, but it is precise enough for this purpose
I hope you do not feel harassed or anything, have a nice time and read the guide/essay.
wintermute