Explanation
A crash cart is a mobile device that consists of a monitor, a keyboard, a mouse, and a network connection. It can be used to access a physical server that is not responding to remote management software or does not have out-of-band management cards configured. The technician can connect the crash cart to the server using a VGA or HDMI cable and troubleshoot the server locally. Verified References: [Crash cart], [Out-of-band management]

Driver updates should be applied to the new components that have been added to a mission-critical server, as part of the server hardening requirements. Drivers are software programs that enable the communication and functionality of hardware devices, such as network cards, storage controllers, or graphics cards. Updating drivers can improve the performance, compatibility, and stability of the new components with the server operating system and applications. References: CompTIA Server+ Certification Exam Objectives, Domain
2.0: Hardware, Objective 2.2: Given a scenario, install, configure and maintain server components.

A kernel upgrade is a process of updating the core component of a Linux operating system that manages the hardware, memory, processes, and drivers. A kernel upgrade can improve the performance, security, and compatibility of the system, but it can also introduce errors if some modules are not compatible with the new kernel version. Modules are pieces of code that can be loaded and unloaded into the kernel to provide additional functionality or support for specific devices. If a module is not compatible with the kernel, it can cause crashes or instability.

Constant replication is a type of replication in which all files are replicated, all the time. Replication is a process of copying data from one location to another for backup, recovery, or distribution purposes. Constant replication is also known as real-time replication or synchronous replication. It ensures that any changes made to the source data are immediately reflected on the target data without any delay or lag. Constant replication provides high availability and consistency, but it requires high bandwidth and low latency. Application consistent replication is a type of replication that ensures that the replicated data is consistent with the state of the application that uses it. It involves quiescing or pausing the application before taking a snapshot of the data and resuming the application after the snapshot is taken. Application consistent replication provides better recovery point objectives than crash consistent replication, which does not quiesce the application before taking a snapshot. Synthetic full replication is a type of replication that involves creating a new full backup by using the previous full backup and related incremental backups. It reduces the backup window and network bandwidth consumption by transferring only changed data from the source to the target. Full replication is a type of replication that involves copying all data from the source to the target regardless of whether it has changed or not. It provides a complete backup of the data, but it requires more storage space and network bandwidth than incremental or differential replication.
References:
https://www.howtogeek.com/199068/how-to-upgrade-your-existing-hard-drive-in-under-an-hour/
https://www.howtogeek.com/202794/what-is-the-difference-between-127.0.0.1-and-0.0.0.0/
https://www.howtogeek.com/443611/how-to-encrypt-your-macs-system-drive-removable-devices-and-individual-files/