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1Z0-060 · Question #202

You use RMAN to back up a database which uses Automatic Storage Management (ASM) and you use the command to back up the ASM metadata regularly. MD_BACKUP You lose an ASM disk group DG1 due to a…

The correct answer is B. Use the MKDG command to add a new disk group DG1 with the same or different specifications D. Use the MD_RESTORE command to restore the disk group metadata and use RMAN to restore. When an ASM disk group is lost, the disk group structure must be recreated first using MKDG or MD_RESTORE before RMAN can restore the data files. These two steps - metadata recovery and data recovery - are handled by separate tools.

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Question

You use RMAN to back up a database which uses Automatic Storage Management (ASM) and you use the command to back up the ASM metadata regularly. MD_BACKUP You lose an ASM disk group DG1 due to a hardware failure. In which two ways can you re-create the lost disk group and restore the data? (Choose two.)

Options

  • AUse RMAN to restore both the metadata and the data.
  • BUse the MKDG command to add a new disk group DG1 with the same or different specifications
  • CUse the MD_RESTORE command to restore both the metadata and data for the failed disk
  • DUse the MD_RESTORE command to restore the disk group metadata and use RMAN to restore

How the community answered

(23 responses)
  • A
    13% (3)
  • B
    83% (19)
  • C
    4% (1)

Why each option

When an ASM disk group is lost, the disk group structure must be recreated first using MKDG or MD_RESTORE before RMAN can restore the data files. These two steps - metadata recovery and data recovery - are handled by separate tools.

AUse RMAN to restore both the metadata and the data.

RMAN manages database data files and does not have the capability to restore ASM disk group metadata; ASM metadata backup and restore are performed exclusively by ASMCMD utilities MD_BACKUP and MD_RESTORE.

BUse the MKDG command to add a new disk group DG1 with the same or different specificationsCorrect

The ASMCMD MKDG command can read from an MD_BACKUP file to recreate disk group DG1 with the same or optionally different disk specifications, re-establishing the ASM structure. Once the disk group exists, RMAN can then restore the database data files into it.

CUse the MD_RESTORE command to restore both the metadata and data for the failed disk

MD_RESTORE only restores the disk group structural metadata such as attributes, disk memberships, and aliases; it does not restore the actual data contained within the disk group, which remains RMAN's responsibility.

DUse the MD_RESTORE command to restore the disk group metadata and use RMAN to restoreCorrect

MD_RESTORE uses the previously created MD_BACKUP file to rebuild the disk group metadata and structure without touching the actual data files. After the disk group structure is restored, RMAN handles the second phase by restoring the database data files into the newly recreated DG1.

Concept tested: ASM disk group recovery using MD_RESTORE and MKDG

Source: https://docs.oracle.com/en/database/oracle/oracle-database/19/ostmg/manage-asm-asmcmd.html

Topics

#ASM metadata backup#MD_RESTORE#disk group recovery#RMAN restore

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