A VM DB system database uses OCI block storage instead of local storage. You specify a storage size when you create the DB system, and you can scale up the storage as required at any time1. Scaling the storage does not affect the availability or performance of the database2. You can use the Oracle Cloud Infrastructure Console or the API to scale the storage of a VM DB system1.

The other options are incorrect because:

• A. After you have provisioned a VM DB system, you cannot increase or decrease block storage. This is false because you can increase or decrease the storage of a VM DB system at any time1.
• C. If you want to increase or decrease the storage, you must change the shape of the VM DB system. This is false because changing the shape of a VM DB system affects the number of CPU cores, not the storage3. You can scale the storage independently of the shape1.
• D. If a VM DB system has different requirements for block storage, you can increase or decrease the storage at any time without impacting the system. This is partially true, but not the best answer. You can increase or decrease the storage at any time, but there is a limitation if you are scaling from a value less than 10,240 GB (10 TB) to a value exceeding 10,240 GB. In that case, you must perform the scaling in two operations2.

References: 1: Scale the DB System 2: About Virtual Machine DB Systems 3: [Change the Shape of a DB System]

The statement that is true about MySQL Database Service is that it is a fully managed Oracle Cloud Infrastructure (OCI) native service1. This means that MySQL Database Service is developed, managed, and supported by the MySQL team in Oracle, and that Oracle automates tasks such as backup and recovery, and database and operating system patching1. You are responsible solely for managing your data, schema designs, and access policies1.

The statements that are false about MySQL Database Service are:

• It is a public cloud service built on MySQL Community Edition. This is false, because MySQL Database Service is built on MySQL Enterprise Edition, which includes advanced features, tools, and support that are not available in MySQL Community Edition2. MySQL Database Service also includes the ability to use HeatWave, an integrated, high-performance, in-memory query accelerator that is not part of MySQL Community Edition3.
• Its users are responsible for database and operating system patching tasks. This is false, because Oracle handles the database and operating system patching tasks for MySQL Database Service, as part of the fully managed service offering1. You do not need to worry about applying patches or updates to your MySQL Database Service instances, as Oracle will do it for you automatically and transparently1.
• It supports MySQL Enterprise Edition version 5.7 with InnoDB Storage Engine. This is false, because MySQL Database Service supports MySQL Enterprise Edition version 8.0 with InnoDB Storage Engine2. MySQL 8.0 is the latest and most advanced version of MySQL, which offers many improvements and enhancements over MySQL 5.72. MySQL Database Service does not support MySQL 5.7 or any other previous versions of MySQL2.

References:

• Overview of MySQL Database Service
• MySQL Database Service Versions
• Overview of MySQL HeatWave Service

To check if cloud tools are up-to-date in Exadata Database Service, you need to perform the following two steps1:

• You must first connect to Exadata Cloud Service as opc and sudo to the root user. This is because the cloud tools are installed and updated by the root user on the database servers1. The opc user is the default administrative user that has sudo privileges to run commands as root1. The oracle user is the default database user that owns the Oracle software and the database files, but it does not have access to the cloud tools1.
• Run the rpm -qa|grep -i dbaastools_exadata command. This command will list the installed packages that match the dbaastools_exadata pattern, which is the name of the cloud tooling package for Exadata Database Service1. The output will show the current version of the cloud tooling package, such as dbaastools_exadata-20.4.1-1.el7.x86_641. You can compare this version with the latest version available from the Oracle Base Database Service documentation1.

The other option, running the dbaascli patch tools list command, is incorrect because it is not a valid command for Exadata Database Service. The dbaascli utility is a command-line interface that provides various functions for managing the database service, such as patching, backup, recovery, and encryption1. However, the patch tools subcommand is not supported for Exadata Database Service, as the cloud tools are automatically updated by Oracle1. Therefore, the correct answer is C and D. References:

• 4: About Oracle Base Database Service - Oracle Help Center