Start and stop instance and Database
To start one or more instances, enter the following SRVCTL syntax from the command line:
srvctl start instance -d db_name -i "inst_name_list"
To stop one or more instances, enter the following SRVCTL syntax from the command line:
srvctl stop instance -d name -i "inst_name_list"
To start or stop your entire cluster database, that is, all of the instances and its enabled services,
srvctl start database -d name
srvctl stop database -d name
All instances in the cluster database use the same SPFILE at startup.
SPFILE location can be an ASM disk group, cluster file system file, or a shared raw device.
SYSTEM syntax enables you to override the effects of SPFILE settings that you make manually.
However, if your SPFILE contains instance-specific settings, then these settings take precedence over settings made with
If another DBA runs the following statement, then Oracle updates the setting on all instances except the instance with sid prod1:
ALTER SYSTEM SET OPEN_CURSORS=1500 sid='*' SCOPE=MEMORY;
In the example instance with sid prod1, the parameter begins accepting
SYSTEM values set by other instances if you change the parameter setting by running the following statement:
ALTER SYSTEM RESET OPEN_CURSORS SCOPE=MEMORY sid='prod1';
Then if you execute the following statement on another instance, the instance with sid prod1 also assumes the new setting of
ALTER SYSTEM SET OPEN_CURSORS=2000 sid='*' SCOPE=MEMORY;
# first comment
OPEN_CURSORS = value # second comment
The following list contains the parameters must be identical on every instance:
you must set a unique value for
INSTANCE_NUMBER for each instance and you cannot use a default value.
Oracle uses the
INSTANCE_NUMBER parameter to distinguish among instances at startup. Oracle uses the
THREAD number to assign redo log groups to specific instances. To simplify administration, use the same number for both the
CLUSTER_DATABASE Enables a database to be started in cluster mode. Set this parameter to
CLUSTER_DATABASE_INSTANCES Sets the number of instances in your RAC environment. A proper setting for this parameter can improve memory use. Set the
CLUSTER_DATABASE_INSTANCES parameter to the same value on all instances.
DB_NAME If you set a value for
DB_NAME in instance-specific parameter files, the setting must be identical for all instances
THREAD If specified, this parameter must have unique values on all instances. The
THREAD parameter specifies the number of the redo thread to be used by an instance
Storage for RAC databases must be shared. In other words, datafiles must reside on
either a cluster file system or on shared raw devices. Additionally, for each instance
you must create at least two redo log files that reside on shared storage devices. You
must also create one shared device for each instance to store its own tablespace for
automatic undo management. If needed, you can use a local file system to store, for
example, client-side parameter files (PFILEs).
To use ASM in RAC, you only need to select ASM as your storage option when you
create your database
When you use ASM, there is an ASM instance on each node of a RAC database. Each
ASM instance has either an SPFILE or PFILE type parameter file.
In RAC, each ASM instance manages all disk and failure groups for each node.
srvctl add asm -n node_name -i asm_instance_name -o oracle_home
Use the following syntax to remove an ASM instance:
srvctl remove asm -n node_name [-i asm_instance_name]
Use the following syntax to enable an ASM instance:
srvctl enable asm -n node_name [-i ] asm_instance_name
Use the following syntax to disable an ASM instance:
srvctl disable asm -n node_name [-i asm_instance_name]
Use the following syntax to start an ASM instance:
srvctl start asm -n node_name [-i asm_instance_name] [-o start_options]
Use the following syntax to stop an ASM instance:
srvctl stop asm -n node_name [-i asm_instance_name] [-o stop_options]
Use the following syntax to show the configuration of an ASM instance:
srvctl config asm -n node_name
Use the following syntax to obtain the status of an ASM instance:
srvctl status asm -n node_name
Each instance has its own online redo log groups which are called an instance's thread
of online redo.
Each instance must have at least two groups of online redo log files in its own thread.
You assign undo tablespaces in your RAC database by specifying a different value for
the UNDO_TABLESPACE parameter for each instance in your SPFILE or individual
PFILEs. You cannot simultaneously use automatic undo management and manual
undo management in a RAC database. In other words, all instances of a RAC database
must operate in the same undo mode.