1z0-902 Practice Questions

For adding a new RAC (Real Application Clusters) VM cluster to an existing Oracle Exadata X9M-2 deployment, you can utilize the Oracle Exadata Deployment Assistant (OEDA). OEDA is available in two interfaces:

OEDA Web-based Configuration Tool: This web-based interface facilitates the configuration of Exadata environments, supporting both physical and virtual deployments. The graphical interface helps in defining VM clusters, including RAC clusters, and ensures the configuration aligns with Oracle best practices​.

OEDA Command Line Interface (CLI): For more advanced or automated tasks, the command-line interface (oedacli) allows for precise control over the deployment process. It supports various configuration actions such as adding or removing clusters, resizing ASM disk groups, and managing VM clusters​.

These tools are specifically designed for Exadata configurations and provide a streamlined approach for deploying and managing RAC clusters in both physical and virtualized environments.

To enable the write-back flash cache on an Exadata X9M-8 storage cell, the existing flash cache must be removed before transitioning to a new mode. This is because the flash cache configuration—whether set to write-through or write-back—requires a re-initialization of the flash storage to apply the new caching behavior. The steps are as follows:

Drop the Existing Flash Cache: Before altering the cache mode, any existing flash cache on the cell must be dropped. This clears the existing configuration and allows the system to reallocate flash resources under the new mode. The command for this is:

# cellcli -e "drop flashcache"

Create a New Flash Cache in Write-Back Mode: After dropping the existing flash cache, you can create a new flash cache with write-back mode enabled. This step ensures that the flash cache is configured correctly to handle write operations before they reach disk, thus accelerating write-heavy workloads. The relevant command to set write-back mode is:

# cellcli -e "create flashcache all"

This process will reset the flash cache with the write-back mode enabled, thereby caching both read and write operations effectively​​.

Exadata storage realms using ASM-scoped security mode allows you to control which database can access which griddisks by creating realms at the ASM level, thereby allowing you to limit the access of each database to the griddisks that it needs to access. This is covered in section 3.15.2 of the Oracle Exadata Database Machine X9M Implementation Essentials Official Text Book and Resources [1].

Exadata storage realms using database-scoped security mode allows you to control which database can access which griddisks by creating realms at the database level [1], thereby allowing you to limit the access of each database to the griddisks that it needs to access. This is covered in section 3.15.3 of the Oracle Exadata Database Machine X9M Implementation Essentials Official Text Book and Resources [2].

[1] https://docs.oracle.com/en/engineered-systems/exadata-database-machine/x9m/exad-implementing-database-machine-x9m.pdf  [2] https://docs.oracle.com/en/engineered-systems/exadata-database-machine/x9m/exad-implementing-database-machine-x9m.pdf

The two valid reasons are:

corruption in the / (root) filesystem . According to 1, this is one of the scenarios that requires a storage server rescue procedure , because it prevents the storage server from booting up normally . The rescue procedure will re-image the root filesystem with a fresh copy of the operating system and restore the configuration files from a backup1.

the failure of both physical M.2 disks . According to 2, each Exadata Storage Server X9M-2 has two physical M.2 disks that store the operating system and configuration files for the storage server . If both M.2 disks fail , then the storage server cannot boot up or function properly . The rescue procedure will replace the failed M.2 disks with new ones and re-image them with the operating system and configuration files2.