[PVE-User] base system restarted

[Muhammad Yousuf Khan]

i am very new to Linux and i am sorry if it is a very beginner  level
question i would request for your help and cooperation. i am using PVE
1.9  on 3 servers. one of my base system which was unexpectedly
restarted or may be hanged (i dont know). but it didn't show the
display then i press the power button it restarted and ping was also
unresponsive.

after the restart everything back to normal and machine sync with the
PVE cluster. however i still couldn't find out what is the problem.

now the help that i need from you guys is which log should i check.

i check dmesg, messages and syslog files but i was confuse that what i
have to look for.  i try to find the word "error"
i couldn't find any i tried several other words but Failed.

so kindly help me in learning  the art of reading logs. :)

Thanks,