Oracle Database records information about important events that occur in your Oracle RAC environment in trace files. The trace files for Oracle RAC are the same as those in noncluster Oracle databases. As a best practice, monitor and back up trace files regularly for all instances to preserve their content for future troubleshooting.
Information about ORA-600 errors appear in the alert_SID.log file for each instance where SID is the instance identifier.
The alert log and all trace files for background and server processes are written to the Automatic Diagnostic Repository, the ___location of which you can specify with the DIAGNOSTIC_DEST initialization parameter. For example:
diagnostic_dest=/oracle/11.1/diag/rdbms/rac/RAC2/trace
Oracle Database creates a different trace file for each background thread. Oracle RAC background threads use trace files to record database operations and database errors. These trace logs help troubleshoot and also enable Oracle Support to more efficiently debug cluster database configuration problems. The names of trace files are operating system specific, but each file usually includes the name of the process writing the file (such as LGWR and RECO). For Linux, UNIX, and Windows systems, trace files for the background processes are named SID_process name_process identifier.trc.
See Also:
Oracle Database Administrator's Guide and Oracle Database 2 Day + Real Application Clusters Guide for more information about monitoring errors and alerts in trace files
Trace files are also created for user processes if you set the DIAGNOSTIC_DEST initialization parameter. User process trace file names have the format SID_ora_process_identifier/thread_identifier.trc, where process_identifier is a 5-digit number indicating the process identifier (PID) on Linux and UNIX systems, and thread_identifier is the thread identifier on Windows systems.