The maximum transmission unit (MTU) is the largest size of a packet or frame that can be sent over a network. Decreasing the MTU size on both servers can reduce the network delay between them, as it can reduce the fragmentation and reassembly of packets, improve the transmission efficiency, and avoid packet loss or errors. Decreasing the MTU size can also avoid taxing other system resources, as it does not require additional CPU, memory, or disk resources. Reference: CompTIA Cloud+ Certification Exam Objectives, page 16, section 3.2

Explanation
A failback is a process of restoring or returning a system or service to its original state or location after a failure or disaster recovery event. Performing a failback is the first action that a cloud administrator should take after successfully completing a DR test and being ready to shut down its DR site and resume normal operations, as it can ensure that all data and configurations are synchronized and consistent between the primary site and the DR site before switching back to the primary site. Performing a failback can also help minimize downtime or disruption, as it can verify that all systems or services are functioning properly before resuming normal operations.
References: CompTIA Cloud+ Certification Exam Objectives, page 10, section 1.5

Explanation
Roles and responsibilities are definitions or descriptions of what each team member or stakeholder is expected to do or perform in a project or process. Roles and responsibilities can help clarify the scope, authority, and accountability of each team member or stakeholder and avoid any confusion or duplication of work. The security team most likely forgot to implement roles and responsibilities when investigating a data breach, as they are all trying to do the same tasks but are interfering with each other's work. Implementing roles and responsibilities can help improve efficiency and effectiveness, as it can ensure that each team member or stakeholder knows what tasks they need to do and how they need to coordinate with others.
References: CompTIA Cloud+ Certification Exam Objectives, page 13, section 2.5

Explanation
A service-level agreement (SLA) is a contract or document that defines the level of service and performance expected from a service provider or vendor. A recovery time objective (RTO) is a metric that specifies the maximum acceptable time for restoring a system or service after a disruption or outage. Both SLA and RTO can provide the data to measure business continuity, as they can indicate the availability, reliability, and recoverability of a system or service in case of a failure or disaster. SLA and RTO can also help evaluate the effectiveness and efficiency of the business continuity plan and solution. References: CompTIA Cloud+ Certification Exam Objectives, page 20, section 4.2