Which two statements are true regarding the configuration of ASM disk groups when installing Oracle Grid Infrastructure 12c?
A.
The installer permits the creation of a disk group for use by the voting disks and OCR file.
B.
If no ASM disk groups are specified during installation, then ASM instances are not started after the installation completes on any cluster node.
C.
The installer permits the creation of a disk group to be used for the Recovery Area for the ASM instance.
D.
If ASM disk groups are configured for the Clusterware files, then ASM must be used for all databases on the cluster.
E.
ASM disk groups used for voting files and OCR files require a quorum failgroup.
Explanation:
You can store Oracle Cluster Registry (OCR) and voting files in Oracle ASM disk groups.
Incorrect Answers:
D: If you install Oracle Database or Oracle RAC after you install Oracle Grid Infrastructure, then you can either use the same disk group for database files, OCR,
and voting files, or you can use different disk groups. If you create multiple disk groups before installing Oracle RAC or before creating a database, then you can do
one of the following:
Place the data files in the same disk group as the Oracle Clusterware files.
Use the same Oracle ASM disk group for data files and recovery files.
Use different disk groups for each file type.
https://docs.oracle.com/database/121/CWLIN/storage.htm#CWLIN488
Oracle ASM is a volume manager and a file system for Oracle database files.Clients that connect directly to ASM include:
• Oracle Database: Oracle Database is the most fundamental ASM client. It makes
requests of ASM relating to numerous types of activities such as ASM File creation.
• ASM Cluster File System: This depends on ASM to provide the ASM volumes.
• ASM Clusterware: If the Oracle Cluster Registry (OCR), voting files, or ASM server
parameter file (SPFILE) is stored on an ASM disk group, the ASM instance is a client of itself.
• ASMCA: ASM Configuration Manager is a graphical interface that allows you to manage
ASM instances, disk groups, and volumes.
• Enterprise Manager: This allows you to manage and monitor the ASM instance
directly, and indirectly through the database.
• Grid Infrastructure: Uses ASM to store the OCR and voting disk files by default.
• SQL clients (such as SQL*Plus): A series of ASM-specific SQL commands (such as
CREATE DISKGROUP) provide the most fundamental management client for ASM.
• ASMCMD: ASM command-line interface is used to interrogate and manage ASM. It
includes many UNIX-like commands that can be used to manage the files and
directories in an ASM system.
——————-
Oracle Clusterware is responsible for node membership and heartbeat monitoring, basic
cluster locking, and node evictions.
Oracle Clusterware is responsible for the startup and shutdown of the ASM instance along with the dependent database instances and resources, as well as resources on which ASM depends.
—————————–
A quorum failure group is a special type of failure group that contains mirror copies of voting files when voting files are stored in normal or high redundancy disk groups.
——————————
Oracle Clusterware uses voting disk files, also called voting disks, to determine which nodes are members of a cluster and to maintain the integrity of the cluster. If you configure voting disks on ASM, you do not need to manually configure the voting disks. Depending on the redundancy of the specified disk group, a predefined number of voting disks are created.ASM manages voting disks differently from other files that it stores. When you initially configure Oracle Clusterware, you specify the disk group to contain the voting disks. Each voting disk is housed in a separate ASM failure group. You must specify enough failure groups to support the number of voting disks associated with each disk group redundancy setting. For example, you must have at least three failure groups to store your voting disks in
a normal redundancy disk group. Voting disks do not appear as regular files within ASM,rather Clusterware records exactly where the voting disk information is located. This arrangement exists so that if ASM is unavailable for any reason, Cluster Synchronization Services can still access the voting disks and maintain the cluster.
One of the benefits of using an ASM disk group, with either normal or high redundancy, is that if a disk containing a voting disk fails, as long as there is another disk available in the disk group, ASM will automatically recover the voting disk. Voting disks are managed using the crsctl utility.
A,E CORRECT I THINK
E is wrong, as you said “A quorum failure group is a special type of failure group that contains mirror copies of voting files when voting files are stored in normal or high redundancy disk groups.” what if the OCR is in an external redundancy?
Correct is A and B
Hello
B answer is correct only when binary installation is done, C and D are wrong and E is good for normal ed high redundancy .
Only answer A is truly correct … try A,E as correct answers.
Regard
I think “A” and “B”, because “E” is not absolutely needed, only in a special cases!
And “B” because a OCR and Vote File is necessary to start the GRID, when you run root.sh… if you don’t have a OCR, where all informations about the instalations will be recorded?
I work with RAC for more than 10 years and i never used a quorum disk!
A quorum failure group is a special type of failure group that does not contain user
data. Quorum failure groups are used for storing Oracle ASM metadata. A quorum
failure group may also contain voting files if those files are stored in a disk group that
contains a quorum failure group. Additionally, Oracle ASM uses a quorum failure
group to help determine if the disk group can be mounted in the event of the loss of
one or more failure groups.
Because disks in quorum failure groups do not contain user data, a quorum failure
group is not considered when determining redundancy requirements in respect to
storing user data.
A,B