All major system log files are located in the /var/log directory in Centos Linux.

• cron — Logs for all cronjobs that are run on the server
• dmesg — Logs from dmesg program which is used to examine or control the kernel ring buffer.
• lastlog — The binary log that contains all of the last login information. (Type “last” to view)
• messages — System logs from syslogd
• mysqld.log — Logs from the mysqld process
• secure — Access logs from the sshd process
• yum.log — Logs from system updates via yum