Database Reference
In-Depth Information
Clusterware Exclusive Mode
Beginning with 11gR2 (11.2.0.2), the cluster stack can be invoked in an exclusive mode to carry out a few exclusive
cluster maintenance tasks, such as restoring OCR and VDs, troubleshooting root.sh issues, and so on. To start the
cluster in this mode on any particular node, the cluster stack must not be active on other nodes in the cluster.
When a cluster is started in exclusive mode, no VD and networks are required. Use the following command as the root
user to bring the cluster in exclusive mode:
$crsctl start crs -excl {-nocrs} {-nowait}
With the -nocrs argument, Oracle Clusterware will be started without the CRSD process, and with the -nowait
argument, Clusterware start doesn't depend on Oracle High Availability Service ( ohasd) daemon start.
Troubleshooting OCR Issues
In the event of any OCR issues, such as logical corruption, missing permissions and ownership, integrity, and loss of
mirror copy, the following troubleshooting and workaround methods are extremely helpful for identifying the root
cause as well as resolving the issues:
Verify the OCR file integrity using the following cluster utilities:
$ocrcheck - verifies OCR integrity & logical corruption
$ocrcheck -config - lists OCR disk location and names
$ocrcheck -local -config - lists LOR name and location
$cluvfy comp ocr -n all -verbose - verifies integrity from all nodes
$cluvfy comp ocr -n rac1 -verbose - verifies integrity on the local node
With the ocrdump utility, you can dump either the entire contents or just a section from the OCR file into a text
file. The following commands achieve that:
$ ocrdump <filename.txt>
-- to obtains a detailed output, run the command as the root user
With the preceding command issued, OCR contents will be dumped into a text file, and if the output filename is
not mentioned, a file named OCRDUMPFILE will be generated in the local directory.
$ ocrdump -stdout -keyname SYSTEM.css {-xml}
The preceding command lists css section-specific contents from the current OCR file, and the contents will be
displayed on the prompt if the output is not diverted into any file.
$ ocrdump -backupfile <filename and location>
-- will dump specific backup contents.
Diagnose, Debug, Trace Clusterware and RAC Issues
When the default debugging information generated by the Oracle Clusterware processes based on their default trace
level settings doesn't provide enough clues to reach a conclusion to a problem, it is necessary to increase the default
trace levels of specific components and their subcomponents to get comprehensive information about the problem.
The default tracing levels of Clusterware components is set to value 2, which is sufficient in most cases.
 
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