Oracle Linux 7.9 is the minimum version required to support RoCE and Persistent Memory. This is because Oracle Linux 7.9 includes kernel enhancements that enable RDMA over Converged Ethernet (RoCE) networking and Intel Optane DC Persistent Memory Modules (DCPMM) for Exadata X8M systems3. These features allow faster access latency and higher throughput for database workloads2.

According to the Oracle Exadata Database Machine documentation12, two recommended configuration best practices for backup and recovery on Exadata are:
1. Placing the backup network on dedicated switches installed in the top of the rack (ToR) has the benefits of isolating the backup network from other workloads and providing a greater level of control.
2. When off-site long-term backup retention is needed, use Oracle Database Backup Cloud Service as a low-cost, offsite scalable storage for a disaster recovery solution.

Exadata Database Machine is a pre-configured and pre-tuned hardware and software system designed to run Oracle Database, it can be installed on raised floor environments, but also on concrete or tile floors Oracle Exadata Database Machine X9M Implementation Essentials states that Exadata racks are designed to be installed on flat surfaces, not raised floor environments. It is not required to install the rack on raised floor environments. Additionally, the other options listed are all requirements for validating, receiving, unpacking, and planning access route and space requirements for Exadata Database Machine. (Source: Oracle Exadata Database Machine X9M Implementation Essentials, page 41)
https://docs.oracle.com/en/engineered-systems/exadata-database-machine/dbmin/index.html

The "cell PMEM cache Read Hits" in the "Database IOs" portion of the "Performance Summary" will show the number of reads that have been satisfied from the Persistent Memory Cache. The "PMEM Cache" section within "Memory Statistics" will give detailed information about the usage of the Persistent Memory Cache, such as cache size, used size, hit rate, etc. This information can help to identify if the Persistent Memory Cache is being used effectively and if there are any issues with it.

This ordering is based on the Oracle Exadata Database Machine X9M Implementation Essentials Official Text Book and other resources. First, the Exadata should be stabilized and unpacked (Steps 2 and 3). Then, the safety guidelines should be reviewed (Step 4). The Exadata should then be allowed to acclimatize for 24 hours (Step 4). After that, the Exadata PDU A should be powered on (Step 6) and the Exadata should be placed in its allocated space (Step 6). Finally, the Exadata PDU B should be powered on (Step 7).