Contents
What is Failgroup in ASM?
Failure groups are used to store mirror copies of data. Each copy is on a disk in a different failure group so that the simultaneous failure of all disks in a failure group does not result in data loss. …
What is ASM redundancy?
Normal redundancy. Oracle ASM provides two-way mirroring by default, which means that all files are mirrored so that there are two copies of every extent. A loss of one Oracle ASM disk is tolerated. You can optionally choose three-way or unprotected mirroring.
What is ASM mirroring?
Maintaining identical copies of data on one or more disks. Typically, mirroring is performed on duplicate hard disks at the operating system level, so that if one of the disks becomes unavailable, the other disk can continue to service requests without interruptions.
What level does ASM perform mirroring?
ASM mirrors at the file level, unlike operating system mirroring, which mirrors at the disk level. Mirroring means keeping redundant copies, or mirrored copies, of each extent of the file, to help avoid data loss caused by disk failures.
What happens when the FAILGRP1 failure group is corrupted?
What happens when the FAILGRP1 failure group is corrupted? A. Mirroring of allocation units occurs within the FAILGRP2 failure group.
Why is ASM needed?
ASM is based on the principle that the database should manage storage instead of requiring an administrator to do it. ASM eliminates the need for you to directly manage potentially thousands of Oracle database files. ASM groups the disks in your storage system into one or more disk groups.
What is the use of ASM?
ASM eliminates the need for you to directly manage potentially thousands of Oracle database files. ASM groups the disks in your storage system into one or more disk groups. You manage a small set of disk groups and ASM automates the placement of the database files within those disk groups.
What is the difference between an RMAN local script and an RMAN global script?
RMAN scripts are only created from the RMAN prompt with the create script command. There is one difference in the making of the global or local scripts and that is the word global while using the create script words. This has created a local script, as you have not used the word global while making it.
How is a disk assigned to a failure group in ASM?
Each disk is assigned to its one failure group in ASM by default. However this assignment of failure groups can be over-ridden by the administrator when creating a disk group or adding a disk to a disk group. The layout of data is then optimized by ASM to reduce the unavailability of data due to failures.
How many failure groups do I need in Oracle?
If you do not specify a failure group for a disk, then Oracle automatically creates a new failure group containing just that disk, except for disk groups containing disks on Oracle Exadata cells. A normal redundancy disk group must contain at least two failure groups.
When to use quorum failure group in ASM?
If configuring an extra failure group presents a problem with storage capacity management, then a quorum failure group can be used as the extra failure group to store a copy of the PST. A quorum failure group does not require the same capacity as the other failure groups. Failure groups can be specified as regular or quorum failure groups.
Are there always failure groups in Oracle Exadata?
There are always failure groups even if they are not explicitly created. If you do not specify a failure group for a disk, then Oracle automatically creates a new failure group containing just that disk, except for disk groups containing disks on Oracle Exadata cells. A normal redundancy disk group must contain at least two failure groups.