Question

ASM : Explain Discovering Disks ? What parameter set ? What happens with out set parameter?

Answer 1

The disk discovery process locates the operating system names for disks that ASM can access. Disk discovery is also used to find all of the disks that comprise a disk group to be mounted. This can include the disks that you want to add to a disk group and the disks that you might consider adding to a disk group.

An ASM instance requires an ASM_DISKSTRING initialization parameter value to specify its discovery strings. Only pathnames that the ASM instance has permission to open are discovered. The exact syntax of a discovery string depends on the platform and ASMLIB libraries. The pathnames that an operating system accepts are always usable as discovery strings.

Answer 2

• ASM_DISKSTRING:
  • Multiple instances can have different values.
  • With shared disk groups, every instance should be able to see the common pool of physical disks.