Log Locations

Common Log Locations:

Apache

Apache Access Logs:
  /usr/local/apache/logs/access_log

Domain access logs:
  /usr/local/apache/domlogs/<DOMAIN>

Site and service error logs:
  /usr/local/apache/logs/error_log

SuExec audit log:
  /usr/local/apache/logs/suexec_log

SuPHP audit log:
  /usr/local/apache/logs/suphp_log

cPanel

Service status:

  /var/log/chkservd.log 

Access and user actions:

  /usr/local/cpanel/logs/access_log

Cpanel Error Logs:

  /usr/local/cpanel/logs/error_log

Database Logs

MySQL database logs:
/var/log/mysqld.log
/var/lib/mysql/$(HOSTNAME).err

PostgreSQL database logs:

  /var/log/pgsql

Exim

(see exim )

Fatal errors:
  /var/log/exim_paniclog

Incoming mail queue:
  /var/spool/exim/input

Exim Messages rejected based on ACLs or other policies:
  /var/log/exim_rejectlog

Exim Delivery and receipt:
  /var/log/exim_mainlog

IMAP, POP login attempts, transactions, fatal errors and spam scoring:
  /var/log/maillog
  /var/log/messages

Mailman Logs:

  /usr/local/cpanel/3rdparty/mailmain/logs

System

Cron:
  /var/log/cron

Ftp Logs:

  /var/log/messages 

  /var/log/xferlog (symlinked to /usr/local/apache/domlogs/ftpxferlog)

Most other logs:
  /var/log/messages

SSH Logs:

  /var/log/secure

Full List of cPanel Logs

Log file location          Description
Cpanel installation logs     /var/log/cpanel-install.log
Cpanel License Logs          /usr/local/cpanel/logs/license_log
Cpanel Login Logs            /usr/local/cpanel/logs/login_log
cPHulk Brute Force Logs      /usr/local/cpanel/logs/cphulkd.log
Cpanel/WHM Accounting (account creations, deletions, etc) Logs     /var/cpanel/accounting.log
Cpanel Bandwidth Logs        /var/cpanel/bandwidth/(account user name)
Cpanel/WHM Service monitor Logs     /var/log/chkservd.log
Cpanel Stats Daemon Logs     /usr/local/cpanel/logs/stats_log
Cpanel backup Logs     /usr/local/cpanel/logs/cpbackup
Update (UPCP) Log     /var/cpanel/updatelogs/update-(TIMESTAMP).log
cPanel/WHM webalizer/awstats logs     /usr/local/cpanel/logs/stats_log
cPanel/WHM version checking     /usr/local/cpanel/version

SquirrelMail     /var/cpanel/squirrelmail
RoundCube        /var/cpanel/roundcube/log
Horde            /var/cpanel/horde/log

tailwatchd log     /usr/local/cpanel/logs/tailwatch_log
EasyApache Build Logs     /usr/local/cpanel/logs/easy/apache/

Tomcat Logs         /usr/local/jakarta/tomcat/logs/catalina.err /usr/local/jakarta/tomcat/logs/catalina.out

ModSecurity Logs    /usr/local/apache/logs/modsec_audit.log /usr/local/apache/logs/modsec_debug_log

Named/Bind (DNS) logs     /var/log/messages

References

cPanel Log Locations Poster:

cPanel Log Locations Poster