Exadata Storage Discovery (Simplified)

ASM_DISKSTRING tells ASM how to find Exadata grid disks. You can use wildcards to discover all disks or filter specific ones, and changes can be applied either dynamically or by restarting ASM.

• Purpose: Oracle ASM needs to know where Exadata grid disks are. This is done using the ASM_DISKSTRING parameter.
• Format of Discovery String:

o/<cell_IP_pattern>/<griddisk_name_pattern>

• <cell_IP_pattern> → IP address of Exadata storage servers (from cellip.ora).
• <griddisk_name_pattern> → Names of grid disks.
• * (wildcard) can be used to match multiple servers or disks.

Examples:

• Discover all grid disks:

ASM_DISKSTRING = 'o/*/*'

Discover only disks starting with DATA:

ASM_DISKSTRING = 'o/*/DATA*'

Changing the Parameter:

• Can be updated while ASM is running using:

ALTER SYSTEM SET ASM_DISKSTRING = '...';

If edited directly in the parameter file, ASM must be shut down and restarted for changes to apply.