In order to completely power off an Exadata Database Machine in an orderly fashion, it's important to properly shut down the cluster first. The command "crscti stop cluster" as root should be executed from one of the database servers.
Once the cluster has been stopped, the next step is to shut down the database servers by executing the command "shutdown -h now" on all database servers.
Next, shut down the Exadata storage servers by executing the command "shutdown -h now" on all Exadata storage servers.
Finally, power off the rack using the power switches on the PDUs.

In order to power off an Exadata Database Machine in an orderly fashion, the commands should be executed in the following order: 1) Execute "crscti stop cluster -all" as the grid user from one database server; 2) Execute "shutdown -h now" on all database servers; 3) Power off all network switches; 4) Execute "shutdown -h now" on all Exadata storage servers; and 5) Power off the rack using the power switches on the PDUs. This sequence of commands ensures that all services running on the Exadata Database Machine are in a clean state before powering off the system. (Source: Oracle Exadata Database Machine X9M Implementation Essentials, page 543)

According to the web search results123, the storage servers in an Exadata Database Machine are mainly used for processing data at the storage level and offloading some SQL operations from the database servers. Therefore, the two activities that are supported on the storage servers are:
A) changing the root password
E) configuring secure shell user equivalency for the cellmonitor user
https://docs.oracle.com/en/engineered-systems/exadata-database-machine/dbmso/exadata-introduction.html

These options are outlined in the Oracle Exadata Database Machine X9M Implementation Essentials official text book and resources. The customer can choose to either provide their own x86 64-Bit gateway hardware or purchase the recommended hardware from Oracle, or they can install the gateway on an Exadata Engineered System.

Exadata Secure RDMA Fabric isolation is a feature that allows you to use virtualization on the X9M-2 platform while maintaining security and isolation between multiple tenants or VM clusters. Secure Fabric isolation works by creating a dedicated network partition and VLAN ID for each Database VM cluster, which is used for cluster networking between the database servers in the VM Cluster. This ensures that the network traffic of each VM cluster is isolated from the others, and it prevents unauthorized access to the data or resources of other VM clusters. Secure Fabric isolation can also be used for other purposes such as client networking, Data Guard traffic, but it's mainly used to provide security and isolation between multiple tenants or VM clusters.