The administrator should identify the runaway process or processes that are causing high load average on the server. Load average is a metric that indicates how many processes are either running on or waiting for the CPU at any given time. A high load average means that there are more processes than available CPU cores, resulting in poor performance and slow response time. A runaway process is a process that consumes excessive CPU resources without terminating or releasing them. A runaway process can be caused by various factors, such as programming errors, infinite loops, memory leaks, etc. To identify a runaway process, the administrator can use tools such as top, ps, or htop to monitor CPU usage and process status. To stop a runaway process, the administrator can use commands such as kill, pkill, or killall to send signals to terminate it.

A single-threaded application is an application that can only execute one task or process at a time. A single-threaded application can only utilize one CPU core, regardless of how many cores are available or assigned to the virtual machine. Therefore, adding more vCPU cores to the VM will not improve the performance of the application, as it will still be limited by the speed and capacity of one core12.
To troubleshoot this issue, the administrator should check if the application is single-threaded or multi-threaded. This can be done by using tools such as Task Manager, Performance Monitor, or Process Explorer on Windows, or top, htop, or ps on Linux34. If the application is single-threaded, the administrator should consider the following options:
* Reduce the number of vCPU cores on the VM to match the number of threads that the application can use. This can help avoid CPU contention and co-stop issues that may arise from having too many vCPUs relative to the number of physical cores on the host5.
* Upgrade the physical CPU on the host to a faster or newer model that can provide higher clock speed and performance for the single core that the application uses.
* Optimize the application code or configuration to make it more efficient or multi-threaded, if possible.
This can help the application take advantage of multiple cores and improve its performance.

An incremental backup only backs up files that have changed since the last backup, whether it was a full or an incremental backup. Therefore, an incremental backup file may require another file to restore data, depending on the sequence of backups. A full backup backs up all files and does not require any other file to restore data.
A snapshot is a point-in-time copy of data that does not depend on other files. A differential backup backs up files that have changed since the last full backup and does not require any other file to restore data.

The administrator should use a subnet mask of 255.255.255.0 for this setup. A subnet mask is a binary number that defines how many bits of an IP address areused for the network portion and how many bits are used for the host portion. The network portion identifies the specific network that the IP address belongs to, while the host portion identifies the specific device within that network. The subnet mask is usually written in dotted decimal notation, where each octet represents eight bits of the binary number. A 1 in the binary number means that the corresponding bit in the IP address is part of the network portion, while a 0 means that it is part of the host portion. For example, a subnet mask of 255.255.255.0 means that the first 24 bits (three octets) of the IP address are used for the network portion and the last 8 bits (one octet) are used for the host portion.
This subnet mask allows up to 254 hosts per network (2^8 - 2). In this case, the IP address of 10.20.10.15 and the default gateway of 10.20.10.254 belong to the same network of 10.20.10.0/24 (where /24 indicates the number of bits used for the network portion), which can be defined by using a subnet mask of 255.255.255.0.

This is the best way to proceed with troubleshooting when the technician has several possible solutions to a reported server issue.
Making one change at a time and testing allows the technician to isolate the cause and effect of each solution and determine which one works best.
It also helps to avoid introducing new problems or complicating existing ones by making multiple changes at once.
Determining whether there is a common element in the symptoms causing multiple problems is a good step to perform before identifying possible solutions, but not after.
Performing a root cause analysis is a good step to perform after resolving the issue, but not during. Documenting the findings, actions, and outcomes throughout the process is a good practice to follow at every step of troubleshooting, but not a specific way to proceed with testing possible solutions.
References:
https://www.howtogeek.com/174288/how-to-tell-if-your-computer-is-overheating-and-what-to-do-about-it/
https://www.howtogeek.com/428483/what-is-end-to-end-encryption-and-why-does-it-matter/