alert file location in 11gStarting from 11g all the diagnostic data (traces, dumps, the alert log) will go under Automatic Diagnostic Repository.
ADR home would be in the following location:
ADR_BASE/diag/product_type/product_id/instance_id
where
product_type --> rdbms
product_id --> database name (my database name t801)
instance_id --> SID (my instance name t801)
ADR Home Subdirectories:So Alert file location will be under following directory:
ADR_BASE/diag/rdbms/t801/t801/alert
If the ORACLE_BASE=/u01/app/oracle then alert file location would be:
/u01/app/oracle/diag/rdbms/t801/t801/alertDIAGNOSTIC_DEST initialization parameter location would be:DIAGNOSTIC_DEST=/u01/app/oracle/
For more detail, read Oracle Documentation: