I must thank my fellow DBA Franky Weber Faust for his publication in his blog.

Introduction: – This article is about creating disk-group via asm cmd. Being an Oracle DBA we have knowledge of ASM. Automatic Storage Management (ASM) is Oracle’s logical volume manager, it uses OMF (Oracle Managed Files) to name and locate the database files. It can use raw disks, file systems or files which can be made to look like disks as long as the device is raw. ASM uses its own database instance to manage the disks, it has its own processes and pfile or spfile, it uses ASM disk groups to manage disks as one logical unit

The benefits of ASM are mention below:-

  • Provides automatic load balancing over all the available disks, thus reducing hot spots in the file system
  • Prevents fragmentation of disks, so you don’t need to manually relocate data to tune I/O performance
  • Adding disks is straight forward – ASM automatically performs online disk reorganization when you add or remove storage
  • Uses redundancy features available in intelligent storage arrays
  • The storage system can store all types of database files
  • Using disk group makes configuration easier, as files are placed into disk groups
  • ASM provides stripping and mirroring (fine and coarse gain – see below)
  • ASM and non-ASM Oracle files can coexist
  • ASM is free!!!!!!!!!!!!!

The status of the disk “AFD: DATA01” is “FORMER” since I had already used it on another disk-group previously and as this risk group was deleted the disk appears with this status.

To create a disk-group using asmcmd it is necessary to generate an XML file and inform some tags.

Let’s see an example:

Include this content in a file using “vi”:

Access the asmcmd utility and create the diskgroup:

If there are no errors in the above procedure the diskgroup will be created successfully.

Let’s check:

As we can see the diskgroup DATA was created successfully.

Note below that it is only mounted on instance 2:

Let’s then mount it remotely in instance 1:

Now we check again to confirm:

From the above article, we get the knowledge about the creation of disk-group by using ASM.

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