Examine this command:
SQl> CREATE DISKGROUP RECO HIGH REDUNDANCY:
FAILGROUP fgrpl1 DISK
‘/dev/disk1’ NAME disk1,
‘/dev/disk2’ NAME disk2,
‘/dev/disk3’ NAME disk3,
FAILGROUP fgrpl2 DISK
‘/dev/disk4’ NAME disk4,
‘/dev/disk5’ NAME disk5,
‘/dev/disk6’ NAME disk6,
FAILGROUP fgrpl3 DISK
‘/dev/disk7’ NAME disk7,http://www.gratisexam.com/
‘/dev/disk8’ NAME disk8,
‘/dev/disk9’ NAME disk9,
ATTRIBUTE ‘au_size’=’4M’,
‘compatible.asm’ = ’12.1’,
‘compatible.rdbms’ = ’12.1’,
‘compatible.advm’ = ’12.1’,
‘content_type’ = ‘recovery’;
Which two statements are true about this disk group?
A.
File created in it have three copies for each allocation unit.
B.
Any database instance with the COMPATIBLE parameter 10.1 and higher can use it.
C.
The Compatible attribute values of the disk group can be changed to lower values.
D.
Files created using a template with the redundancy attributes set to MIRROR will have three-way Mirroring.
E.
The RECO diskgroup may only be used for the FRA.
F.
Files created using a template with the redundancy attribute set to HIGH will have three-way mirroring.
Explanation:
For Oracle ASM to mirror files, specify the redundancy level as NORMAL REDUNDANCY (2-way mirroring by default for most file types) or HIGH REDUNDANCY
(3-way mirroring for all files).
Note:
When a file is created, redundancy and striping attributes are set for that file based on an explicitly named template or the system template that is the default
template for the file type.
Incorrect Answers:
B: Compatible.rdbms is set to 12.1, not to 10.1.
C: The compatible attributes cannot be reversed.
D: With the MIRROR redundancy attribute, the file is written to a disk in one failure group, a mirrored copy of the file is written to a disk in another failure group.
E: FRA (Flash Recovery Area) is not referenced in the creation of the diskgroup.
https://docs.oracle.com/cd/B28359_01/server.111/b28286/statements_5008.htm
A,F
Hi Ziad
D is also correct. I will choose D and F
check here
http://docs.oracle.com/database/121/SQLRF/statements_1009.htm#SQLRF52648
redundancy_clause
Specify the redundancy level of the newly added or modified template:
MIRROR: Files to which this template are applied are protected by mirroring their data blocks. In normal redundancy disk groups, each primary extent has one mirror extent (2-way mirroring). For high redundancy disk groups, each primary extent has two mirror extents (3-way mirroring). You cannot specify MIRROR for templates in external redundancy disk groups.
HIGH: Files to which this template are applied are protected by mirroring their data blocks. Each primary extent has two mirror extents (3-way mirroring) for both normal redundancy and high redundancy disk groups. You cannot specify HIGH for templates in external redundancy disk groups.
UNPROTECTED: Files to which this template are applied are not protected by Automated Storage Management from media failures. Disks taken offline, either through system action or by user command, can cause loss of unprotected files. UNPROTECTED is the only valid setting for external redundancy disk groups. UNPROTECTED may not be specified for templates in high redundancy disk groups. Oracle discourages the use of unprotected files in high and normal redundancy disk groups.
Hi edge
I agree with you D,F
but we need to search which is the best 2 choices between A,D,F because in the real exam they will ask to choose best 2 ?
http://docs.oracle.com/database/121/SQLRF/statements_1009.htm#BABDDHBB
redundancy_clause
Specify the redundancy level of the newly added or modified template:
MIRROR: Files to which this template are applied are protected by mirroring their data blocks. In normal redundancy disk groups, each primary extent has one mirror extent (2-way mirroring). For high redundancy disk groups, each primary extent has two mirror extents (3-way mirroring). You cannot specify MIRROR for templates in external redundancy disk groups.
HIGH: Files to which this template are applied are protected by mirroring their data blocks. Each primary extent has two mirror extents (3-way mirroring) for both normal redundancy and high redundancy disk groups. You cannot specify HIGH for templates in external redundancy disk groups.
A and F
I don’t think A is correct: is every extent which will have three copies, no each AU
For me, D and F
The rule:
“When a disk group is created, Oracle ASM creates a set of default templates for that disk group. The set consists of one template for each file type (data file, control file, redo log file, and so on) that is supported by Oracle ASM. …. Default template settings depend on the disk group type. The default template for data files for a normal redundancy disk group sets two-way mirroring, while the corresponding default template in a high redundancy disk group sets three-way mirroring. You can modify these default templates.”
See: https://docs.oracle.com/cd/E11882_01/server.112/e18951/asmfiles.htm#BABJGIAE
Table 7-5 Permitted values for Oracle ASM template redundancy attribute
For a diskgroup with HIGH redundancy in a diskgroup and the template attribute set to MIRROR it will be a 3-way mirror. You are correct, D and F
But, see table 7-6, all types os template files has MIRROR as default, than “A” is correct! Unless you create a personal template to change it!
In the course of RAC/ASM 10g, 11g and 12c
https://docs.oracle.com/cd/E11882_01/server.112/e18951/asmfiles.htm#g2223792
AH! Ok! i got it… “extent” not “AU”
The correct: “D” and “F”
Big thanks beatrizia!
you are correct. 100% D, F
The justification for A being wrong may be that, if we have reduced redundancy (i.e. one disk failed and there is not enough free space to recreate the third copy for all AUs), there may be AUs left with only two copies.
In the exam it’s asking which three statements are correct in this diskgroup?
Correct Answer: A,D,F