After running the commands above, the filesystem mounted on /u01 is on the logical volume /dev/mapper/VGExaDb-LVDbOral. So, to add 20G of space to the filesystem mounted on /u01, the command that needs to be run is:
lvextend -L +20G --verbose /dev/mapper/VGExaDb-LVDbOral
This command will extend the logical volume /dev/mapper/VGExaDb-LVDbOral by 20 GB of space. It is important to note that the option --verbose is used to display the progress of the operation.

When multiple databases share space on the storage servers in an unpartitioned storage grid, two Exadata security features can be configured to control which databases can access which griddisks.
Exadata storage realms using ASM-scoped security mode: This feature allows you to create storage realms and assign them to specific databases. This allows you to control which databases have access to which griddisks. The ASM-scoped security mode applies to all griddisks within an ASM disk group, which means that all griddisks in a disk group will be accessible only to the databases that belong to the assigned storage realm.
File permissions on the griddisks in each storage server: This feature allows you to configure file permissions on the griddisks at the storage server level. You can assign specific permissions to specific users or groups, allowing you to control which databases can access which griddisks.

Auto Service Request (ASR) will raise service requests for component failures in RoCE network interface cards in the storage servers, fans in the storage servers, power distribution units, and power supplies in the database servers. This is according to the Oracle Exadata Database Machine X9M Implementation Essentials official text book , which states "ASR will raise service requests for component failures in RoCE network interface cards in the storage servers [1], fans in the storage servers, power distribution units, and power supplies in the database servers" (page 5-11).

According to Oracle.com documents or resources, the three options that are available for database consolidation on Exadata are:
1. Multiple pluggable databases in one or more container databases on a Virtual Machine or Bare Metal cluster123.
2. A single database with one or more schema per application12.
3. Multiple Databases on a cluster12.
https://blogs.oracle.com/exadata/post/database-consolidation-why-and-how