Difference on using SRVCTL and CRSCTL commands:
Use SRVCTL to manage Oracle-supplied resources such as
Listener,
Instances,
Disk groups,
Networks.
Use CRSCTL for managing Oracle Clusterware and its resources.
Oracle strongly discourages directly manipulating Oracle-supplied resources (resources whose names begin with ora) using CRSCTL. This could adversely impact the cluster configuration.
If resource name begins with ora then use SRVCTL
RMAN-06169: could not read file header for datafile nn error reason 4
RMAN-06169: could not read file header for datafile nn error reason 4
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of backup command at 10/20/2011 07:41:54
RMAN-06056: could not access datafile nn
The reason code of 4 meant for DBWR could not find the file. After investigating found that the new data file added on locally for a RAC database. That data file not available on other node cause this backup failure.
To resolve this, the locally create data file moved to ASM.
The command is oracle@DB_Node2:/home/oracle $ ocrconfig –showbackup
Since, the OCR Automatic backups are taken only by master node. We can verify with following command.
DB_Node1 2011/08/07 22:50:25 /app/crs/product/11g/cdata/PRDDB_cluster/backup00.ocr |
| Here the Master node is DB_Node1 |
To find the preferred node in Oracle RAC from the configuration. It find the details from Oracle Cluster Registry (OCR). It displays the Oracle Restart configuration information
| $ srvctl config service -d db01 |
To find the status of the services, on which instances, it is running
| $ srvctl status service -d db01 |
To relocate the services from one node to another or one instance to another
| srvctl relocate service -d db_unique_name -s service_name {-c source_node -n target_node | -i old_instance_name -t new_instance_name} [-f] |
What is Service in Oracle RAC?
Services allow you granular definition of workload and the DBA can dynamically define which instances provide the service. Connection Load Balancing (provided by Oracle Net Services) still needs to be set up to allow the user connections to be balanced across all instances providing a service.
When administrating a RAC system use the dictionary views of GV$ and not V$.
GV$ has additional columns inst_id .
For almost every V$ view described in this chapter, Oracle has a corresponding GV$ (global V$) view. In Real Application Clusters, querying a GV$ view retrieves the V$ view information from all qualified instances.
In addition to the V$ information, each GV$ view contains an extra column named INST_ID of datatype NUMBER. The INST_ID column displays the instance number from which the associated V$ view information was obtained. The INST_ID column can be used as a filter to retrieve V$ information from a subset of available instances
| GV$ | V$ |
| Across all the nodes: The beauty of system dictionary views of GV$ which reflect information across the various nodes of a RAC system | Only the current node The V$ views of the data dictionary, which relate to the current status of the single node you are connected to |
For example;
| select distinct(username) from v$session; |
It only reflects connections to the connected node and not the entire RAC.
Whereas;
| select distinct(username) from gv$session; |
It gives the view of all sessions within the RAC.
The GV$ dictionary views have the additional INST_ID column which give the node that the action is occurring in
