Database Alert log, OUI log, ASM Alert log, CRS Log, OS Watcher log and OS Messages Location Listed at one Place

Performance Tuning

When working as Remote DBA log files plays very important role in day to day monitoring and trouble shooting. Log file checking starts from Software installation and continue through out life of database. Now a days, Database is not just a single s/w to work upon, Real Application Cluster and Automatic Storage Management has became an integral part of it.

Sometimes remote DBA also needs to look into OS level logs as well. Here, I am trying to give a central place for all database related log files like Database Alert log, OUI log, ASM Alert log, CRS Log, OS Watcher log and OS Messages Location.

Let’s start from Oracle Database Software Installation. Oracle Universal Installer (OUI) is commonly used tool for s/w installation.

  1. Oracle Universal Installer (OUI) log Files (Oracle 9.2.0.X.X, 10.1.0.X.X, 10.2.0.X.X and 11.2.0.X.X ): The log files are in /logs directory.

In Unix the location of central inventory (oraInventory) can be found from the oraInst.loc file, which exists in the /var/opt/oracle or /etc/ (By default).

[[email protected] etc]$ pwd
[[email protected]]$ cat oraInst.loc

Oracle Installer Location File Location

Thu Oct 21 16:12:34 PDT 2010


Here, the inventory_loc is ‘/etc/oraInventory’

The log files are below:

/logs/silentInstall.log (only for Silent installations)

For 10.2.0.X.X to 11.2.0.X.X only

/cfgtoollogs/oui/silentInstall.log (only for Silent installations)

  1. Database alert log: Database Alert log are files, where every database related activities are recorded like instance start, stop, redo log switching, ORA error etc.

A DBA need to check this file for two reasons.

a. To check health of Database.
b. Check details of any error in Database.

In Oracle 11g Default path for Alert log files is


Ex: /u01/app/oracle/diag/rdbms/db01/db001/trace/alert_db001.log

In Oracle 10g Environment, use below command to find path for alter log files.

SQL> show parameter background_dump_dest


background_dump_dest string /etc/oracle/diag/rdbms/testdb/testdb/trace

  1. Automatic Storage Management alert log files: ASM is used for providing redundancy and balancing data and load across different disks. Any issue related to ASM below is the path for alter log files (Oracle 11g).

$ORACLE_BASE/diag/asm/+asm/+ASM{instance number}/trace/ alert_+ASM {instance number}.log
Ex: /u01/app/oracle/diag/asm/+asm/+ASM2/trace/alert_+ASM2.log

  1. Clusterware CRS alert log: Real application Cluster is used for high availability and work load distribution among diff-2 servers. To check health of cluster and trouble shooting below is path for alter log file.

The following sections describe the locations of the clusterware log files in Database Software Oracle 10g Release 1.

Cluster Ready Services Log Files

Cluster Ready Services (CRS) has daemon processes that generate log information. Log files for the CRS daemon (crsd) can be found in the following directories:


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


Cluster Synchronization Services (CSS) Log Files
You can find CSS information that the OCSSD generates in log files in the following locations:


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


Oracle High Availability Log Files
The Oracle RAC high availability trace files are located in:


Where $ORACLE_BASE is configured and $ORACLE_HOME/racg/log when $ORACLE_BASE is not available.

In Oracle 11g Release 1 onwards logs can be found at this location.

$GRID_HOME/log/{node name}/alert{node name}.log
Ex: /u01/app/11.2.0/grid/log/db02/alertdb02.log

  1. Diskmon log files : Disk mon log are basically to check any issue with the disk in the system.

$GRID_HOME/log/{node name}/diskmon/diskmon.lo*
Ex: /u01/app/11.2.0/grid/log/dmorldb02/diskmon/diskmon.log

  1. OS Watcher output files : OS watcher logs are helpful for remote DBA when Database Server is hang or reboot automatically. Below is path for Linux/Unix env.


To get OS watcher data of specific date :
cd /opt/oracle.oswatcher/osw/archive
find . -name ‘12.01.13‘ -print -exec zip /tmp/ {} \;
where 12- year 01- Month 13-day

  1. Os message logfile: OS message log file are logs related to OS related messages. Path for Linux/Unix syatem is below.



Log Directory Structure in Cluster Ready Services

To diagnose any problem, the first thing examined by Oracle Support are the installation log files. Anyone who knows anything about database administration knows the importance of the dump directories (bdump, udump, and cdump). Similarly, each component in the CRS stack has its respective directories created under the CRS home:

$ORA_CRS_HOME/crs/log Contains trace files for the CRS resources.
$ORA_CRS_HOME/crs/init Contains trace files of the CRS daemon during startup. Good place to start with any CRS login problems.
$ORA_CRS_HOME/css/log The Cluster Synchronization (CSS) logs indicate all actions such as reconfigurations, missed check-ins, connects, and disconnects from the client CSS listener. In some cases, the logger logs messages with the category of auth.crit for the reboots done by Oracle. This could be used for checking the exact time when the reboot occurred.
$ORA_CRS_HOME/css/init Contains core dumps from the Oracle Cluster Synchronization Service daemon (OCSSd) and the process ID (PID) for the CSS daemon whose death is treated as fatal. If abnormal restarts for CSS exist, the core files will have the format of core. .
$ORA_CRS_HOME/evm/log Log files for the Event Volume Manager (EVM) and evmlogger daemons. Not used as often for debugging as the CRS and CSS directories.
$ORA_CRS_HOME/evm/init PID and lock files for EVM. Core files for EVM should also be written here.
$ORA_CRS_HOME/srvm/log Log files for Oracle Cluster Registry (OCR), which contains the details at the Oracle cluster level.
$ORA_CRS_HOME/log Log files for Oracle Clusterware (known as the cluster alert log), which contains diagnostic messages at the Oracle cluster level. This is available from Oracle database 10g R2.