ASM_DISKSTRING

Property	Description
Parameter type	String
Syntax	ASM_DISKSTRING = discovery_string [, discovery_string ] ...
Default value	The null string; Automatic Storage Management discovery finds all disks in an operating system-specific location to which the Automatic Storage Management instance has read/write access.
Modifiable	ALTER SYSTEM
Real Application Clusters	Multiple instances can have different values. Different nodes might see the same disks under different names; however, each instance must be able to use its ASM_DISKSTRING to discover the same physical media as the other nodes in the cluster.

Note:

1. This parameter may only be specified in an Automatic Storage Management instance.

ASM_DISKSTRING specifies an operating system-dependent value used by Automatic Storage Management to limit the set of disks considered for discovery. When a new disk is added to a disk group, each Automatic Storage Management instance that has the disk group mounted must be able to discover the new disk using the value of ASM_DISKSTRING.

In most cases, the default value will be sufficient. Using a more restrictive value may reduce the time required for Automatic Storage Management to perform discovery, and thus improve disk group mount time or the time for adding a disk to a disk group. A "?" at the beginning of the string gets expanded to the Oracle home directory. Depending on the operating system, wildcard characters can be used. It may be necessary to dynamically change ASM_DISKSTRING before adding a disk so that the new disk will be discovered.

An attempt to dynamically modify ASM_DISKSTRING will be rejected and the old value retained if the new value cannot be used to discover a disk that is in a disk group that is already mounted.

2. This parameter was introduced in 10g.

3. Query for the current value of the parameter

select name, value, isdefault, isses_modifiable, issys_modifiable,

isinstance_modifiable, isdeprecated, description

from v$parameter where upper(name) = 'ASM_DISKSTRING';

NAME	VALUE	IS DEFAULT	ISSES_ MODIFIABLE	ISSYS_ MODIFIABLE	ISINSTANCE_ MODIFIABLE	IS DEPRECATED	DESCRIPTION
asm_diskstring		TRUE	FALSE	IMMEDIATE	TRUE	FALSE	disk set locations for discovery

Oracle initializatoin parameters

ASM_DISKGROUPS

Property	Description
Parameter type	String
Syntax	ASM_DISKGROUPS = diskgroup [, diskgroup ] ...
Default value	There is no default value.
Modifiable	ALTER SYSTEM
Range of values	Comma-separated list of strings, of up to 30 characters
Real Application Clusters	Multiple instances can have different values.

Note:

This parameter may only be specified in an Automatic Storage Management instance.

ASM_DISKGROUPS specifies a list of names of disk groups to be mounted by an Automatic Storage Management instance at instance startup or when an ALTER DISKGROUP ALL MOUNT statement is issued.

Automatic Storage Management (ASM) automatically adds a disk group to this parameter when the disk group is successfully created or mounted, and automatically removes a disk group from this parameter when the disk group is dropped or dismounted.

Issuing the ALTER DISKGROUP...ALL MOUNT or ALTER DISKGROUP...ALL DISMOUNT command does not affect the value of this parameter.

Note:

1.Query for the current value of the parameter

select name, value, isdefault, isses_modifiable, issys_modifiable,

isinstance_modifiable, isdeprecated, description

from v$parameter where upper(name) = 'ASM_DISKGROUPS';

NAME	VALUE	IS DEFAULT	ISSES_ MODIFIABLE	ISSYS_ MODIFIABLE	ISINSTANCE_ MODIFIABLE	IS DEPRECATED	DESCRIPTION
asm_diskgroups		TRUE	FALSE	IMMEDIATE	TRUE	FALSE	disk groups to mount automatically

Oracle initializatoin parameters

ARCHIVE_LAG_TARGET

Property	Description
Parameter type	Integer
Default value	0 (disabled)
Modifiable	ALTER SYSTEM
Range of values	0 or any integer in [60, 7200]
Basic	No
Real Application Clusters	Multiple instances should use the same value.

ARCHIVE_LAG_TARGET limits the amount of data that can be lost and effectively increases the availability of the standby database by forcing a log switch after the specified amount of time elapses.

A 0 value disables the time-based thread advance feature; otherwise, the value represents the number of seconds. Values larger than 7200 seconds are not of much use in maintaining a reasonable lag in the standby database. The typical, or recommended value is 1800 (30 minutes). Extremely low values can result in frequent log switches, which could degrade performance; such values can also make the archiver process too busy to archive the continuously generated logs.

Note:

1. Query for the current value of the parameter

select name, value, isdefault, isses_modifiable, issys_modifiable,

isinstance_modifiable, isdeprecated, description

from v$parameter where upper(name) = 'ARCHIVE_LAG_TARGET';

NAME	VALUE	IS DEFAULT	ISSES_ MODIFIABLE	ISSYS_ MODIFIABLE	ISINSTANCE_ MODIFIABLE	IS DEPRECATED	DESCRIPTION
archive_lag_target	0	TRUE	FALSE	IMMEDIATE	TRUE	FALSE	Maximum number of seconds of redos the standby could lose

Oracle initializatoin parameters

AQ_TM_PROCESSES

Property	Description
Parameter type	Integer
Default value	None
Modifiable	ALTER SYSTEM
Range of values	0 to 10
Basic	No

AQ_TM_PROCESSES controls time monitoring on queue messages and controls processing of messages with delay and expiration properties specified.You do not need to specify a value for this parameter because Oracle Database automatically determines the number of processes and autotunes them, as necessary. Therefore, Oracle highly recommends that you leave the AQ_TM_PROCESSES parameter unspecified and let the system autotune.

Note:

1. If you want to disable the Queue Monitor Coordinator, then you must set AQ_TM_PROCESSES to 0 in your parameter file. Oracle strongly recommends that you do NOT set AQ_TM_PROCESSES to 0. If you are using Oracle Streams, then setting this parameter to zero (which Oracle Database respects no matter what) can cause serious problems.

2. A number of internal database features rely on the AQ_TM_PROCESSES having a value other than 0 so explicitly setting this parameter to 0 can lead to some features appearing not to work as expected. In 10.2 a warning is written to the alert if this parameter has been set to 0 – See Metalink Note 428441.1

3. Query for the current value of the parameter

select name, value, isdefault, isses_modifiable, issys_modifiable,

isinstance_modifiable, isdeprecated, description

from v$parameter where upper(name) = 'AQ_TM_PROCESSES';

NAME	VALUE	IS DEFAULT	ISSES_ MODIFIABLE	ISSYS_ MODIFIABLE	ISINSTANCE_ MODIFIABLE	IS DEPRECATED	DESCRIPTION
aq_tm_processes	1	FALSE	FALSE	IMMEDIATE	TRUE	FALSE	number of AQ Time Managers to start

Oracle initializatoin parameters

ACTIVE_INSTANCE_COUNT

Property	Description
Parameter type	Integer
Default value	There is no default value.
Modifiable	No
Range of values	1 or >= the number of instances in the cluster. (Values other than 1 have no effect on the active or standby status of any instances.)
Basic	No
Real Application Clusters	You must set this parameter for every instance, and multiple instances must have the same value.

Note:

1. This parameter functions only in a cluster with only two instances.

ACTIVE_INSTANCE_COUNT enables you to designate one instance in a two-instance cluster as the primary instance and the other instance as the secondary instance. This parameter has no functionality in a cluster with more than two instances.

When you set this parameter to 1, the first instance you start up becomes the primary instance and accepts client connections. The second instance starts up as a secondary instance and can accept client connections only if the first instance fails. In such an event, the secondary instance becomes the primary instance.

When the failed instance can once again be started up, it starts up as the secondary instance, and will not accept client connections unless the current primary instance fails.

2. Query for the current value of the parameter

select name, value, isdefault, isses_modifiable, issys_modifiable,

isinstance_modifiable, isdeprecated, description

from v$parameter where upper(name) = 'ACTIVE_INSTANCE_COUNT';

NAME	VALUE	IS DEFAULT	ISSES_ MODIFIABLE	ISSYS_ MODIFIABLE	ISINSTANCE_ MODIFIABLE	IS DEPRECATED	DESCRIPTION
active_instance_count		TRUE	FALSE	FALSE	FALSE	FALSE	number of active instances in the cluster database

Oracle initializatoin parameters