When starting up your ASM instance, you receive the following error:
What is the cause of the error?
A.
The ASM_DISKGROUPS parameter is configured for three disk groups: DGROUP1,
DGROUP2, and DGROUP3. The underlying disks for these disk groups have apparently been
lost.
B.
The format of the ASM_DISKGROUPS parameter is incorrect. It should reference the disk
group numbers, not the names of the disk groups
C.
The ASM_POWER_LIMIT parameter is incorrectly set to 1. It should be set to the number of
disk groups being attached to the ASM instance.
D.
The ASM_DISKSTRING parameter is not set; therefore disk discovery is not possible.
E.
There is insufficient information to solve this problem.
D is wrong answer. From documentation:
“The default value of the ASM_DISKSTRING parameter is a NULL string. A NULL value causes Oracle ASM to search a default path for all disks in the system to which the Oracle ASM instance has read and write access. ”
http://docs.oracle.com/cd/E11882_01/server.112/e18951/asminst.htm#BHCEHJGA
and
How A Disk is Discovered
http://docs.oracle.com/cd/E11882_01/server.112/e18951/asmdiskgrps.htm#CHDHDDBE
I think idem that Justin, A is a correct answer, read teh folow text:
ASM_DISKSTRING The ASM_DISKSTRING parameter specifies one or more operating system dependent strings to limit the disk devices that can be used to create disk groups. If this value is NULL, all disks visible to the ASM instance are potential candidates for creating disk groups.