Oracle Oracle Certifications 1Z0-053 Questions & Answers

• Question 641:

  What is the proper command to shut down the database in a consistent manner?

  A. shutdown abort

  B. shutdown kill

  C. shutdown nowait

  D. shutdown immediate

  E. shutdown halt

  Correct Answer: D

• Question 642:

  As the DBA, you run the following query on your ASM instance. What is the implication of the results of the query? (Choose two.)

  SQL> select group_number, name, state from v$ASM_DISKGROUP;

  GROUP_NUMBER NAME STATE ============ ======= ========== 0 DGROUP1 DISMOUNTED 2 DGROUP2 MOUNTED 3 DGROUP3 MOUNTED

  A. The DGROUP1 disk group was unmounted by another DBA.

  B. A datafile has been lost, causing the ASM disk group DGROUP1 to go into the DISMOUNTED state

  C. One of the redundant disks (DGROUP1) has been lost in a disk group.

  D. This query has no meaning in an ASM instance.

  E. A disk associated with a disk group was discovered after the ASM instance initially opened.

  Correct Answer: AE

• Question 643:

  You are an Oracle DBA responsible for an ASM instance. The disk controller on your system fails. You suspect that the disk itself is okay. You know it will take 24 hours to replace the controller and you don't want to have to rebuild the disks from scratch.

  What do you do?

  A. Take the whole disk group offline and wait for the controller card to be installed. Once it's installed, bring the disk group online again.

  B. Change the ASM parameter ASM_PREFERRED_READ_FAILURE_GROUPS to indicate that you want to read from the non-failed disk. Once the disk controller is replaced, reset the parameter to its original value.

  C. You have no choice but to rebuild the disk. Drop the disk from the disk group and wait for the controller to be replaced. Once the controller is replaced, add the disk back into the disk group and allow ASM to rebuild it.

  D. If you are using any setting other than REDUNDANCY EXTERNAL for your disk group, you will have to recover any data on that disk from a backup. The database will be unavailable until you can correct the problem and perform recovery.

  E. Change the attribute DISK_REPAIR_TIME on the disk group to a time greater than 24 hours.

  Correct Answer: E

• Question 644:

  If you use ALTER DISKGROUP ... ADD DISK and specify a wildcard for the discovery string, what happens to disks that are already a part of the same or another disk group?

  A. The command fails unless you specify the FORCE option.

  B. The command fails unless you specify the REUSE option.

  C. The command must be reissued with a more specific discovery string.

  D. The other disks, already part of the disk group, are ignored.

  Correct Answer: C

  Refer to an Oracle Example for adding disk to diskgroup (link) How A Disk is Discovered

  While an ASM instance is initialized, ASM discovers and examines the contents of all of the disks that are in the paths that you designated with values in the ASM_DISKSTRING initialization parameter. Disk discovery also occurs when you:

  Run the ALTER DISKGROUP...ADD DISK and ALTER DISKGROUP...RESIZE DISK commands Query the V$ASM_DISKGROUP and V$ASM_DISK views

  Disk Discovery Rules(link)

  The rules for discovering ASM disks are as follows:

  ASM can discover up to 10,000 disks. That is, if more than 10,000 disks match the ASM_DISKSTRING initialization parameter, then ASM discovers only the first 10,000.

  ASM only discovers disks that contain a partition table.

  Note:

  ASM does not discover a disk that contains an operating system partition table, even if the disk is in an SM disk string search path and ASM has read and write permission for the disk.

  When adding a disk, the FORCE option must be used if ASM recognizes that the disk was managed by Oracle. Such a disk appears in the V$ASM_DISK view with a status of FOREIGN. In this case, you can only add the disk to a disk group

  by using the FORCE keyword.

  In addition, ASM identifies the following configuration errors during discovery:

  Multiple paths to the same disk

  In this case, if the disk is part of a disk group, then disk group mount fails. If the disk is being added to a disk group with the ADD DISK or CREATE DISKGROUP command, then the command fails. To correct the error, adjust the

  ASM_DISKSTRING value so that ASM will not discover multiple paths to the same disk. Or if you are using multipathing software, then ensure that you include only the pseudo-device name in the ASM_DISKSTRING value. See "ASM and

  Multipathing".

  Multiple ASM disks with the same disk header

  This can be caused by having copied one disk onto another. In this case, the disk group mount operation fails.

• Question 645:

  The following command is executed to shut down an Automatic Storage Management (ASM) instance: SQL>SHUTDOWN ABORT;

  Which two statements describe the consequences of the above command? (Choose two.)

  A. The disk groups are orderly dismounted.

  B. The ASM instance requires recovery when it is started.

  C. The database instance that are currently clients of the ASM instance are aborted.

  D. The CSS daemon stops and has to be restarted before the ASM instance is restarted.

  Correct Answer: BC

• Question 646:

  Which two commands never trigger an implicit rebalancing within the disk group?. (Choose two.)

  A. ALTER DISKGROUP misc MOUNT;

  B. ALTER DISKGROUP misc DROP DISK misc2;

  C. ALTER DISKGROUP misc CHECK ALL NOREPAIR;

  D. ALTER DISKGROUP misc RESIZE ALL SIZE 1023m;

  E. ALTER DISKGROUP dgroupA ADD DISK '/devices/A*';

  Correct Answer: AC

  Altering Disk Groups

  You can use the ALTER DISKGROUP SQL statement to alter a disk group configuration. You can add, resize, or drop disks while the database remains online. Whenever possible, multiple operations in a single ALTER DISKGROUP

  statement are recommended. Grouping operations in a single ALTER DISKGROUP statement can reduce rebalancing operations. Oracle ASM automatically rebalances when the configuration of a disk group changes. By default, the ALTER

  DISKGROUP statement does not wait until the operation is complete before returning. Query the V$ASM_OPERATION view to monitor the status of this operation.

  add_disk_clause

  Use this clause to add one or more disks to the disk group and specify attributes for the newly added disk.

  Oracle ASM automatically rebalances the disk group as part of this operation.

  drop_disk_clause

  Use this clause to drop one or more disks from the disk group.

  DROP DISK

  The DROP DISK clause lets you drop one or more disks from the disk group and automatically rebalance the disk group. When you drop a disk, Oracle ASM relocates all the data from the disk and clears the disk header so that it no longer is

  part of the disk group. The disk header is not cleared if you specify the FORCE keyword.

• Question 647:

  In which situations will the ASM metadata backup help you recover the ASM disk in a disk group? (Choose all that apply.)

  A. when one or more file directory paths are accidentally deleted from an ASM disk group

  B. when one of the disks in a disk group is accidentally unplugged

  C. when the data file on an ASM disk group gets corrupted

  D. when one or more disks in an ASM disk group are lost

  Correct Answer: AD

• Question 648:

  Examine the CREATE DISKGROUP command used to create a disk group:

  SQL> CREATE DISKGROUP misc EXTERNAL REDUNDANCY DISK 'ORCL: FRA3' NAME misc1, 'ORCL: FRA4' NAME misc2;

  In which situation would you use this method of disk group creation?

  A. When two-way disk mirroring is required for the allocation units

  B. When three-way disk mirroring is required for the allocation units

  C. When using hardware mirroring or RAID

  D. When disk mirroring is required for the Automatic Storage Management (ASM) disks

  Correct Answer: C

• Question 649:

  You issued the following command to mount the DATA disk group in restricted mode: ALTER DISKGROUP data MOUNT RESTRICT;

  What is the implication of this command?

  A. The client RDBMS instance can access the file as a read-only file.

  B. A new disk cannot be added to a disk group.

  C. A disk in a disk group can be taken offline.

  D. The client RDBMS instance cannot access the files in the disk group.

  Correct Answer: D

  MOUNT (link)

  Specify MOUNT to mount the disk groups in the local Oracle ASM instance. Specify ALL MOUNT to mount all disk groups specified in the ASM_DISKGROUPS initialization parameter. File operations can only be performed when a disk group

  is mounted. If Oracle ASM is running in a cluster or a standalone server managed by Oracle Restart, then the MOUNT clause automatically brings the corresponding resource online. RESTRICTED | NORMAL Use these clauses to determine

  the manner in which the disk groups are mounted.

  In the RESTRICTED mode, the disk group is mounted in single-instance exclusive mode. No other Oracle ASM instance in the same cluster can mount that disk group. In this mode the disk group is not usable by any Oracle ASM client.

  In the NORMAL mode, the disk group is mounted in shared mode, so that other Oracle ASM instances and clients can access the disk group. This is the default.

• Question 650:

  

  You are managing an Oracle Database 11g database with ASM storage. The ASM disk group has the COMPATIBLE.ASM attribute set to 11.1.

  Which statements are true regarding extent management and allocation units in the ASM disk group? (Choose all that apply.)

  A. The au_size disk group attribute determines the size of allocation units in the disk group.

  B. The allocation unit size may vary but the extent size is fixed.

  C. The allocation unit size and extent size are fixed for all the disks in a disk group and cannot be changed.

  D. Extent management is completely automated.

  Correct Answer: AD