ODA : Enabling Local File System Auditing Can Greatly Slow Down the Database IO Performance

Asset ID:	1-72-2088220.1
Update Date:	2015-12-28
Keywords:

Solution Type Problem Resolution Sure

Solution 2088220.1 : ODA : Enabling Local File System Auditing Can Greatly Slow Down the Database IO Performance

Related Items


Oracle Database Appliance X4-2
 Oracle Database Appliance X3-2

Related Categories


PLA-Support>Eng Systems>Exadata/ODA/SSC>Oracle Database Appliance>DB: ODA_EST
 Tools>Primary Use>Performance

We ran some SQL that is known to run in 100ms on another ODA and 5s on this ODA.  With syslog running it reliably and consistently takes 5s to run.  With syslog stopped it reliably and consistently takes 100ms

Created from <SR 3-11499868481>

Applies to:

Oracle Database Appliance X3-2 - Version All Versions to All Versions [Release All Releases]
Oracle Database Appliance X4-2 - Version All Versions to All Versions [Release All Releases]
Information in this document applies to any platform.

Symptoms

SQL that is known to run in 100 ms on another ODA is only taking 5s on a different ODA:

With syslog running the SQL consistently takes 100s to run.
With syslog stopped the same SQL consistently takes 5m.

[kjournald]
syslogd -m 0

The symptoms can be confirmed in the OSW output including IOSTAT

...
...
sdaw 0.00 204.00 0.00 196.00 0.00 1604.00 16.37 1.32 6.74 4.85 95.00
sdaw1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
sdaw2 0.00 204.00 0.00 196.00 0.00 1604.00 16.37 1.32 6.74 4.85 95.00
sdaw 0.00 74.00 0.00 166.00 0.00 964.00 11.61 0.98 5.92 5.78 95.90

Changes

Enabled audit file on local file system.

Cause

Too much audit file generation on the local file system caused bad performance.

Solution

Turn off and change the level of database auditing.

Attachments

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