Automatic Storage Management is installed by default with Oracle Universal Installer. The Database Configuration Assistance (DBCA) looks for an existing ASM instance and if it does not find one, there is the option of creating and configuring one during the installation process. It is available in both the Enterprise Edition and Standard edition Installations.
Starting Up ASM Instance
An ASM instance is started like any other database instance, except that the initialization parameter file contains the parameter instance_type=ASM.
For ASM instances, the mount option does not try to mount a database, but tries to mount the diskgroups that are specified by the asm_diskgroups parameter. ASM instance requires smaller SGA (64MB) and usually brought up automatically on server reboots.
NOMOUNT:- does not mount any disk groups, but starts up the instance.
MOUNT:- mounts the disk goups specified by asm_diskgroups.
OPEN:- not valid for ASM instance.
FORCE:-issues the command shutdown abort to the instance and starts it as in normal database instance.
Shuting down ASM Instance
NORMAL:-ASM waits for any in-progress SQL to complete before performing an orderly dismount of all of the disk groups.
ASM waits for all of the currently connected users to disconnect from the instance.
If any database instances are connected to the ASM instance, then the SHUTDOWN command returns an error.
NORMAL:-ASM waits for any in-progress SQL to complete before performing an orderly dismount of all of the disk groups.
ASM waits for all of the currently connected users to disconnect from the instance.
If any database instances are connected to the ASM instance, then the SHUTDOWN command returns an error.
IMMEDIATE or TRANSACTIONAL:-ASM waits for any in-progress SQL to complete before performing an orderly dismount of all of the disk groups.
ASM does not wait for users currently connected to the instance to disconnect.
If any database instances are connected to the ASM instance, then the SHUTDOWN command returns an error.
Because the ASM instance does not contain any transactions, the TRANSACTIONAL mode is the same as the IMMEDIATE.ABORT:-The ASM instance immediately shuts down without the orderly dismount of disk groups.
This causes recovery to occur upon the next ASM startup.
If any database instance is connected to the ASM instance, then the database instance aborts.
Initialization Parameter Files for an ASM Instance
Below are the list of asm parameters, i'll only explain the relevant ones.
ASM_DISKGROUPS:-Name of the disk groups created.
ASM_DISKSTRING:- limits the set of disks that ASM considers for discovery.
ASM_POWER_LIMIT:- The maximum power on an ASM instance for disk rebalancing. Possible values range from 1 to 11 with 11 being the fastest.
INSTANCE_TYPE:- Must be set to ASM, this is the only required parameter. All other parameters assume defaults values for most environments.
LARGE_POOL_SIZE:- Internal packages used by ASM utilize the Large Pool. The value of large_pool_size should be set ot a value greater than 8MB.
DB_CACHE_SIZE:-
DIAGNOSTIC_DEST:-
ASM_DISKSTRING:- limits the set of disks that ASM considers for discovery.
ASM_POWER_LIMIT:- The maximum power on an ASM instance for disk rebalancing. Possible values range from 1 to 11 with 11 being the fastest.
INSTANCE_TYPE:- Must be set to ASM, this is the only required parameter. All other parameters assume defaults values for most environments.
LARGE_POOL_SIZE:- Internal packages used by ASM utilize the Large Pool. The value of large_pool_size should be set ot a value greater than 8MB.
DB_CACHE_SIZE:-
DIAGNOSTIC_DEST:-
PROCESSES:-
REMOTE_LOGIN_PASSWORDFILE:-
SHARED_POOL_SIZE:-
REMOTE_LOGIN_PASSWORDFILE:-
SHARED_POOL_SIZE:-
ASM_PREFERRED_READ_FAILURE_GROUPS:-
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