Oracle Solution for Error ora-15130

ORA-15130: diskgroup "string" is being dismounted

What triggered the Error:

The diskgroup is being dismounted by request or because an I/O error was encountered that could not be handled by taking the disks offline. A disk cannot be offlined whenever doing so could result in all copies of a redundant extent being unavailable.

What should we do to fix it:

Repair the hardware problem and re-mount the diskgroup. Refer to the alert log to determine which disks have failed.