You are administering a database stored in Automatic Storage Management (ASM). You use
RMAN to back up the database and the MD_BACKUP command to back up the ASM metadata
regularly. You lost an ASM disk group DG1 due to hardware failure.
In which three ways can you re-create the lost disk group and restore the data?
A.
Use the MD_RESTORE command to restore metadata for an existing disk group by passing
the existing disk group name as an input parameter and use RMAN to restore the data.
B.
Use the MKDG command to restore the disk group with the same configuration as the backedup disk group and data on the disk group.
C.
Use the MD_RESTORE command to restore the disk group with the changed disk group
specification, failure group specification, name, and other attributes and use RMAN to restore the
data.
D.
Use the MKDG command to restore the disk group with the same configuration as the backedup disk group name and same set of disks and failure group configuration, and use RMAN to
restore the data.
E.
Use the MD_RESTORE command to restore both the metadata and data for the failed disk
group.
F.
Use the MKDG command to add a new disk group DG1 with the same or different specifications
for failure group and other attributes and use RMAN to restore the data.
Explanation:
Note:
*Themd_restorecommand allows you to restore a disk group from the metadata created by
themd_backupcommand.
/md_restore Command
Purpose
This command restores a disk group backup using various options that are described in this
section.
/ In the restore mode md_restore, it re-create the disk group based on the backup file with all userdefined templates with the exact configuration as the backuped disk group. There are several
options when restore the disk group
full – re-create the disk group with the exact configuration
nodg – Restores metadata in an existing disk group provided as an input parameter
newdg – Change the configuration like failure group, disk group name, etc..
* The MD_BACKUP command creates a backup file containing metadata for one or more disk
groups. By default all the mounted disk groups are included in the backup file which is saved in the
current working directory. If the name of the backup file is not specified, ASM names the file
AMBR_BACKUP_INTERMEDIATE_FILE.
I think A C F.
I think A ,D ,F.
I think C ,D ,F.
A – wrong, b’cuz md_restore command restores disk groups from a metadata backup file. Input parameter is backupfile, not disk group
B- wrong. B’cuz MKDG creates disk group based on xml configuration file. It doesn’t restore.
C – Correct. B’cuz MD_RESTORE command restores disk groups. “newdg” option let’s you specify the new name. Then RMAN can be used to restore the data
D- Wrong. as said in B
E – I’m not sure if MD_RESTORE can restore “data” as well? if so, why do we need to restore from RMAN
F- correct. We can create new disk and restore data usin RMAN
E : should be correct. Misread earlier…with this option there is no need to re-store from RMAN.
I take it back.
‘A’ should be answer instead of E . Per documentation, The md_restore command restores disk groups from a metadata backup file.. I doesn’t include data itself.
So DG names should be provided to tell which DG to restore, then use RMAN to bring data.
See nice demo
http://jvardhan.blogspot.com/2012/03/oracle-backup-utility-rman-only-provide.html
Agree with ACF
not sure
Most possibly C E F
Praveen, you should read the documentation: http://docs.oracle.com/cd/E11882_01/server.112/e18951/asm_util004.htm#OSTMG94584
Concerning A, the -G option allows to select a disk group to restore and is an input parameter. And with –nodg you can restore metadata for an existing diskgroup, as proposed by the answer A. You are right, A is wrong, but not for the good reason.
We lost the diskgroup DG1, it is not possible to restore from the existing diskgroup, since the disk group itself is missing in this context.
Concerning D, you can use MKDG to recreate a disk group even if it does not really mean a “restore”. Recreate the disk group with MKDG and restore data with RMAN is a valid solution anyway. You just need the XML file.
Concerning E, MD_RESTORE and MKDG cannot restore any data. It restores meta data only. You can only use RMAN. In ASM, the solution is always recreate the ASM disk group first, and use RMAN to restore the data.
Bye
Hi Michael, Thanks for your input.
Concerning D – is wrong answer from a question point of view because MKDG can not be used to restore the disk group.
My take for correct answer is – ACF.
Thanks,
Pradeep
ACF
MD_RESTORE command restore diskgroup not data we need use RMAN
DKDG – create = restore and restore data with RMAN
A – NOT
B – NOT
E – NOT
C – OK
D – OK
F – OK
http://www.oracle-class.com/?p=1930
Can any one confirm the correct answer?
AEF
CDF
Correct Answer – C,D,F
A is not correct as per the below test result.
ASMCMD> md_restore /usr/users/oragrid/dg_data1 –silent –full -G DATA1
Current Diskgroup metadata being restored: DATA1
ORA-15018: diskgroup cannot be created
ORA-15030: diskgroup name “DATA1” is in use by another diskgroup (DBD ERROR: OCIStmtExecute)
ASMCMD-9352: CREATE DISKGROUP failed
ORA-15018: diskgroup cannot be created
ORA-15030: diskgroup name “DATA1” is in use by another diskgroup (DBD ERROR: OCIStmtExecute)
D is correct
ASMCMD> mkdg /tmp/tt.xml
ASMCMD> lsdg
State Type Rebal Sector Block AU Total_MB Free_MB Req_mir_free_MB Usable_file_MB Offline_disks Voting_files Name
MOUNTED EXTERN N 512 4096 1048576 153597 153538 0 153538 0 N DATA1/
MOUNTED NORMAL N 512 4096 1048576 15345 4666 5115 -224 0 Y VOCR/
ASMCMD> !cat /tmp/tt.xml
C, F r correct. Not D. MKDG cmd would create dg, not restore
CDF – as D is a sub process of F!
ACF
From the docs (A is right based on the second example)
The first example restores the disk group data from the backup script and creates a copy. The second example takes an existing disk group data and restores its metadata. The third example restores disk group data completely but the new disk group that is created is named data2. The fourth example restores from the backup file after applying the overrides defined in the override.sql script file.
ASMCMD [+] > md_restore –-full –G data –-silent /scratch/backup/alldgs20100422
ASMCMD [+] > md_restore –-nodg –G data –-silent /scratch/backup/alldgs20100422
ASMCMD [+] > md_restore –-newdg -o ‘data:data2’ –silent /scratch/backup/data20100422
ASMCMD [+] > md_restore -S override.sql –silent /scratch/backup/data20100422
ACF
for me, ACF!!!
CEF
C, D, F
Following Oracle Database 12c: Backup and Recovery Workshop page 11-8:
* Use the ASMCD md_restore command to restore ASM disk group from a metadata backup file.
* In the event of a loss of the ASM disk group, the metadata backup file can be used to reconstruct the disk group and its metadata rather than re-creating the disk group manually.
* Restore options:
— full: Create a disk group and restores metadata
— nodg: Restores metadata only
— newdg -o: Creates a disk group with a different name than the original disk group and restores the metadata.
Restoring ASM Disk Groups: Examples
———————————–
* Restoring all disk groups in the metadata file:
ASMCMD> md_retsore /backup/asm_metadata –full
* Retoring the metadata only for the DATA disk group:
ASMCMD> md_retsore /backup/asm_metadata –nodg -G data
* Creating a SQL script to restore the DATA disk group
ASMCMD> md_retsore /backup/asm_metadata -full -S asmql.sql -G data
Demonstration:
http://orabase.org/index.php/exam-prepare/1z0-060-prepare/1z0-060-q5/
ACF
http://satya-dba.blogspot.ca/2010/02/asmcmd-10g-11g.html
ASMCMD> md_restore -b /tmp/backup.txt -t full -g data
ASMCMD> md_restore –t newdg –of override.txt –i backup_file
Example restores the diskgroup asmdsk1 from the backup script and creates a copy.
ASMCMD> md_restore –t full –g asmdsk1 –i backup_file
Example takes an existing diskgroup asmdsk6 and restores its metadata.
ASMCMD> md_restore –t nodg –g asmdsk6 –i backup_file
Example restores diskgroup asmdsk1 completely but the new diskgroup that is created is called asmdsk2.
ASMCMD> md_restore –t newdg -o ‘asmdsk1:asmdsk2’ –i backup_file
Example restores from the backup file after applying the overrides defined in the file override.txt.
ASMCMD> md_restore –t newdg –of override.txt –i backup_file
Example restores the diskgroup data from the backup script and creates a copy.
ASMCMD [+] > md_restore –-full –G data –-silent /tmp/dgbackup20090714
Example takes an existing diskgroup data and restores its metadata.
ASMCMD [+] > md_restore –-nodg –G data –-silent /tmp/dgbackup20090714
Example restores diskgroup data completely but the new diskgroup that is created is called data2.
ASMCMD [+] > md_restore –-newdg -o ‘data:data2’ –silent /tmp/dgbackup20090714
Example restores from the backup file after applying the overrides defined in the override.sql script file.
ASMCMD [+] > md_restore -S override.sql –silent /tmp/dgbackup20090714
ASMCMD> md_restore -b dg7.backup -t full -f cr8_dg7.sql
On exam there were only 5 options and only 3 of them contains data restoring with RMAN (2 with MD_RESTORE and one with MKDG). It easy to choose right answer
A is not correct. Although restore metadata portion is ok, the action not adequate to answer question. Question is “In which three ways can you re-create the lost disk group and restore the data?”
Need to restore metadata, asm disk groups then restore data with RMAN.
md_restore or mkdg cannot restore actual data, is always using RMAN
my choices CDF