From the technical background, we have an idea of Validations. I talk about normal life we notice that we have lots of Validations in our life. Let’s have look at today about ASM (Sector Size Validations). First few lines will explain the technical definition of  Validations.

Validation is the name given to the process whereby the information entered in the database is checked to ensure that it makes sense. For example, you can use validation to check that only numbers between 0 and 100 are entered in a percentage field, or only Male or Female is entered in a sex field. It cannot check that it is correct (the process of checking that the data is actually right is called verification).

 

Now we have deep knowledge of Sector Size Validations.

  • ASM prevents disks of different sector sizes from being added to the same disk group. It occurs during CREATE DSI GROUP, ALTER DISKGROUP ADD DISK and ALTER DISKGROUP MOUNT operations.
  • If the sector_size attributes are explicitly specified when creating a disk group. ASM  attempts to verify that all disk discovered through each search strings have a sector size equal to the specified value.
  • ASM  also attempts to verify disk sector size during the mount operation an the mount fails if one or more disks have a sector size different from the SECTOR_SIZE value.
  • If DBA do not specify the sector_size attribute when creating a disk group and ASM can verify that all discovered disks have the same sector value, then that values are assumed for the disk group sector size that is created.  in case if the disks have different sector sizes, the create operation fails.
  • DBA must ensure that new disks to be added to have the same value as the SECTOR_SIZE disk group attribute during new disks are added to an existing disk group using ALTER DISKGROUP, ADD DISK SQL Statement.

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