How to find out the reason for a server shutdown on Debian?

Question

linux

Hello all specialists,
I have had one problem on my server for a week now. It turns off by itself, I think it’s hard to load something, it hasn’t happened before, I can’t understand why, and I can’t understand it freezes or stupidly turns off. Each time you need to manually reboot.
What should be done? Where to see?
Thank you all in advance.

Answer 1

Start by looking at /var/log/messages

Answer 2

At the moment of freezing, etc. look at the screen (IP-KVM to help), perhaps Kernel Panic

Answer 3

First check the iron - in particular, the state of cooling. Then - in logs.

Answer 4

1 read logs: messages, dmesg is the server being monitored? Are there any anomalies in the CPU metrics, memory, etc.?
2 we test hardware - we drive percents and memory, we watch smart hard drives
3 if it is a server and there is IPMI then when it freezes you can go through the IPMI interface to see what is happening on the screen, you can also see the IPMI controller logs, it can report some hardware problems.
4 if there is a suspicion of a kernel panic, then we put Kdump