If you are using RAC system (doesnt matter how many nodes you have) You need to know where log files are located.

In this post, I share those log files locations.

Here We go;

The Cluster Ready Services Daemon (crsd) Log Files

Log files for the CRSD process (crsd) can be found in the following directories:

                 CRS home/log/hostname/crsd

Oracle Cluster Registry (OCR) Log Files

The Oracle Cluster Registry (OCR) records log information in the following location:

                CRS Home/log/hostname/client

Cluster Synchronization Services (CSS) Log Files

You can find CSS information that the OCSSD generates in log files in the following locations:

                CRS Home/log/hostname/cssd

Event Manager (EVM) Log Files

Event Manager (EVM) information generated by evmd is recorded in log files in the following locations:

                CRS Home/log/hostname/evmd

RACG Log Files

The Oracle RAC high availability trace files are located in the following two locations:

CRS home/log/hostname/racg

$ORACLE_HOME/log/hostname/racg

Core files are in the sub-directories of the log directories. Each RACG executable has a sub-directory assigned exclusively for that executable. The name of the RACG executable sub-directory is the same as the name of the executable.

You can follow below table which define locations of logs files:

Oracle Clusterware log files

Cluster Ready Services Daemon (crsd) Log Files:
$CRS_HOME/log/hostname/crsd

Cluster Synchronization Services (CSS):
$CRS_HOME/log/hostname/cssd

Event Manager (EVM) information generated by evmd:
$CRS_HOME/log/hostname/evmd

Oracle RAC RACG:
$CRS_HOME/log/hostname/racg
$ORACLE_HOME/log/hostname/racg

Oracle RAC 11g Release 2 log files

Clusterware alert log:
$GRID_HOME/log/<host>/alert<host>.log

Disk Monitor daemon:
$GRID_HOME/log/<host>/diskmon

OCRDUMP, OCRCHECK, OCRCONFIG, CRSCTL:
$GRID_HOME/log/<host>/client

Cluster Time Synchronization Service:
$GRID_HOME/log/<host>/ctssd

Grid Interprocess Communication daemon:
$GRID_HOME/log/<host>/gipcd

Oracle High Availability Services daemon:
$GRID_HOME/log/<host>/ohasd

Cluster Ready Services daemon:
$GRID_HOME/log/<host>/crsd

Grid Plug and Play daemon:
$GRID_HOME/log/<host>/gpnpd:

Mulitcast Domain Name Service daemon:
$GRID_HOME/log/<host>/mdnsd

Event Manager daemon:
$GRID_HOME/log/<host>/evmd

RAC RACG (only used if pre-11.1 database is installed):
$GRID_HOME/log/<host>/racg

Cluster Synchronization Service daemon:
$GRID_HOME/log/<host>/cssd

Server Manager:
$GRID_HOME/log/<host>/srvm

HA Service Daemon Agent:
$GRID_HOME/log/<host>/agent/ohasd/oraagent_oracle11

HA Service Daemon CSS Agent:
$GRID_HOME/log/<host>/agent/ohasd/oracssdagent_root

HA Service Daemon ocssd Monitor Agent:
$GRID_HOME/log/<host>/agent/ohasd/oracssdmonitor_root

HA Service Daemon Oracle Root Agent:
$GRID_HOME/log/<host>/agent/ohasd/orarootagent_root

CRS Daemon Oracle Agent:
$GRID_HOME/log/<host>/agent/crsd/oraagent_oracle11

CRS Daemon Oracle Root Agent:
$GRID_HOME/log/<host> agent/crsd/orarootagent_root

Grid Naming Service daemon:
$GRID_HOME/log/<host>/gnsd