Log files

Useful log files

Main useful one is

/var/log/messages

and contains the majority of the useful information the system produces.

There's some other useful ones depending what you're doing.

Ldap stuff? /var/log/ldap

cron stuff? /var/log/cron

Security/access stuff you'll either want /var/log/secure or maybe stuff in /var/log/sssd/ folder.