1z0-902 Exam Dumps : Oracle Exadata Database Machine X9M Implementation Essentials

On Exadata systems, ASM disk group configurations require that:

Grid Disks Must Have Similar Performance Characteristics: Within a disk group, grid disks must not only be of the same size but also need to exhibit similar performance traits. This consistency ensures balanced I/O operations and optimizes the performance for ASM mirroring and striping across disks​.

Sparse Diskgroups: These are specialized virtual objects that reside within the DATA disk group. Sparse diskgroups are used to support snapshots and other space-efficient storage solutions by creating virtual representations of grid disks within an existing disk group without consuming additional physical space​.

These characteristics are fundamental to ensuring that ASM maintains optimal performance and storage efficiency on Exadata platforms.

Once the physical disk has been replaced, you will need to create a new celldisk and griddisks on the replaced physical disk. After the griddisks have been dropped from the associated ASM diskgroups, you can then add the griddisks back into the ASM diskgroup they used to be a member of and rebalance the data on the effected griddisks. Finally, you should verify that the griddisks located on the physical disk have been successfully dropped from the associated ASM diskgroups.

To enable REST access to the MS process, you need to manually enable the REST services on each storage server by running the command cellcli -e "ALTER CELL ENABLE REST" and then configure authentication and authorization to ensure secure access. This is described in detail in the Oracle Exadata Database Machine X9M Implementation Essentials Official Text Book (Chapter 8, Securing the Exadata Database Machine).