OCP-043 ASM_DISKSTRING
60. You are using an Automatic Storage Management (ASM) instance to manage the files of your
production database. While studying the parameter file of the ASM instance, you find the following entry:
ASM_DISKSTRING = /devices/*
What could be the reason for this setting?
A.to enable the ASM instance to identify the alert log file
B.to enable the ASM instance to identify the server parameter file
C.to enable the ASM instance to define the locations for Oracle Managed Files (OMF)
D.to enable the ASM instance to identify all disks that can be accessed by it in the /devices directory
Answer: D
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:
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_DISKSTRINGbefore 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.