Updated March 17, 2023

Definition of Oracle ASM

Oracle ASM is the feature of the oracle database that provides simplified storage to Oracle customers for managing consistent and server storage platforms. By using oracle automatic storage management, we can manage the small number of pools called disk groups of ASM. All the database-related files we can assign to the disk group of ASM, and we can manage ASM and data layout organizations to ensure optimal performance.

Key Takeaways

An instance of ASM is clustered by using Clusterware, there is a single Oracle instance of every cluster node.
If there are multiple database instances for a different node, then it will share a single ASM instance. ASM is using the disk group for storing the data.

What is Oracle ASM?

Disk provides convenient and consolidated storage for administrative tasks, previously it is handled by DBA and system administrators. It provides underlying storage management for the file system of the ASM cluster which provides centralized storage of data.

It is nothing but the volume manager or a file system of oracle database that supports a single instance of Oracle database and Oracle RAC. It is the Oracle Corporation-managed solution that provides alternative file systems. It will use the disk groups for storing the data files, it will contain the collection of a disk that Oracle will manage as a unit.

Why Oracle ASM?

Below are the key features that show why we are using Oracle ASM in our environment. It contains multiple benefits and is important to use ASM in our environment.

IO channel takes advantage of software mirroring and data stripping.
We can easily automate the redistribution of data as per the addition and removal of disk space.
It contains redundant copies and it provides for third-party RAID functionality.
It supports third-party IO technologies.
It needs to diminish hot spares.

By using it we can add and remove the disk from the database to continue access files from the group of a disk. When we add or remove the disk from the disk group, oracle ASM automatically redistribute the file contents and also it eliminate the need for downtime.

How does Oracle ASM Work?

Oracle ASM is an integrated file system built specifically for files of Oracle databases. It will simplify the administration of the database by eliminating the need of directly managing multiple files. It is done by enabling all the available storage in the units called disk groups. We can manage a small set of disk groups.

Below is the component of Oracle ASM from which ASM is working as follows:

ASM files – It will automatically simplify and manage the layout of data files, log files, and control files. Database files are automatically distributed across all the available disks and configuration changes of storage.
ASM disks – The ASM disk belongs to the group of disks. On Windows, the OS disk group always contains partitions in other platforms disk group is LUN or network attached file.
ASM disk group – The disk group consists of the disk collection that is managed as a unit. It contains the primary component of ASM. We can configure the ASM by creating the disk groups which stores the database files.
ASM templates – The ASM template is nothing but the attribute value used to set the mirroring of each database file that was created in ASM disk groups. Each disk group will contain the default template.
Failure groups – This is an ASM disk that shares a common failure mechanism. It is used to determine which ASM disk is used to store redundant data.

Oracle ASM Disk

It is the device of storage that was provisioned into the disk groups of Oracle ASM.

Below is an example of Oracle ASM disks as follows:

Storage array disk partition
Logical volumes
NFS (Network attached file)
Entire disk of partition of a disk

At the time of adding a disk to the disk group, we can assign a name to the Oracle ASM disk or it will be assigned a disk name automatically. This name of the disk is different from the path name that was defined by OS. In a single cluster, the disk can assign different device names of the operating system on different nodes but the disk contains the same ASM disk name.

In a specified cluster the disk is accessed from all instances that are sharing the disk group. It is spreading files proportionally across all the disk groups. This pattern of allocation is maintaining each disk of the same capacity.

Oracle ASM Groups

Every disk group contains the metadata required for disk group space management. The components of Oracle ASM groups are as follows. Oracle ASM group contains various components.

It will include the following components as follows:

Files
Disks
Allocation units

For multiple installations we have required a small number of disk groups, we require two or more than three disk groups. We are using file components in Oracle ASM groups for storing the database data. We are storing data in a number of files. We can also use disks for storing the data by using Oracle ASM. We can also allocate multiple units of a block by using it.

Oracle ASM Storage

The storage functionality provides flexible server monitoring options. It has high redundancy and a normal storage group enabling two and three-way mirroring. We can also use external redundancy for enabling the redundant array for the independent disk storage for performing the function of mirroring protection.

Storage also uses the features of oracle managed files for simplifying database management. It will automatically be creating the file in a designated location. The oracle managed files also renamed the storage files as per requirement.

Storage is removing the administrative overheads for managing the storage of the database, it will consolidate data into multiple disk groups. The small number of disk groups is consolidating the storage into multiple databases and it will be providing improved IO performance.

Benefits

The Oracle ASM is a logical volume manager it will use the managed files for locating the database files. It will be using raw disks or files, it will use its instance of database also it will contain its spfile and pfile for managing the logical unit of a disk.

Below are the benefits of Oracle ASM as follows:

It is providing automatic load balancing onto all disks, so it will reduce hotspots of a file system.
It will contain previous fragmentation of the disk, so we don’t need to manually relocate the data.
To add the disk in a database is straightforward, ASM will automatically perform online disk allocation.
Redundancy of user, the feature is available in the storage arrays.
Storage system is storing all types of database files.
By using a disk group the configuration of data files is easier.
It is providing mirroring and stripping.
It is free.
It will contain Oracle ASM and non-ASM files.

Importance

It is simplifying the oracle administration files while allowing the administrator for referencing to the disk groups rather than individual files that are managed by ASM. We are using new ASM functionality for a combination of cooked and raw file systems. It will not contain the full database, it’s a memory structure and lightweight.

It will contain automatic and simplified storage management.
It will be increasing the storage utilization agility.
It is delivering scalability, availability, and predictive performance.
It will support the database failure when the server will crash.
It is integrated with the managed server.

FAQs

Given below are the FAQs mentioned:

Q1. What is the use of Oracle ASM?

Answer: It is used to store the data files. It contains a different type of data file to store the data.

Q2. What is the use of disk in Oracle ASM?

Answer: Disk is nothing but a storage device that is provided by ASM disk groups. We need to assign the name of the Oracle ASM disk at the time of adding.

Q3. What is the use of disk groups in Oracle ASM?

Answer: The oracle disk group consists the multiple disks and it contains the fundamental objects to manage the disk group.

Conclusion

Oracle ASM is nothing but the volume manager or a file system of oracle database that supports a single instance of Oracle database and Oracle RAC. It is the Oracle Corporation-managed solution that provides alternative file systems. It is the feature of the oracle database that provides simplified storage to Oracle customers to manage consistent and server storage platforms.

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