I must thank my fellow DBA Franky Weber Faust for his publication in his blog.
The goal here is to introduce how to create a disk group with one of the new features of Oracle ASM in version 12.2.0.1, the Flex Redundancy or Flex Disk Group.

This new type of Disk Group redundancy in ASM allows us to isolate databases at different levels of redundancy. For example, PROD_PDB will have High Redundancy, while HML_PDB and DEV_PDB will have Normal Redundancy.

Let’s go step by step …

Initially I introduce new disks to ASM using the Filter Driver

We list the disks to check the newly added:

When you exit ASMCMD switch your session to the oracle user and set the environment variables again to the + ASM1 instance and access SQL * Plus:

To use Flex redundancy requires at least 3 Failure Groups, therefore 3 disks.

Note that in the build command I did not report any Failure Group, but by default ASM creates one for each of the disks. Let’s see:

And Disk Group looks like this:

Let’s delete Disk Group to create it again:

Then we include the 3 disks and create again specifying the path of each disk and also their respective Failure Groups:

Since we have 5 disks we will use the remaining 2 and add them in separate Failure Groups:

We list the disks again to see how it was after we all used them:

Finally we verified how the distribution of the space in the Disk Groups was:

In the next post we will see how to use this Flex Disk Group.

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