The Best Backup Type for Fast Restoration

A.

The best backup type to perform prior to installing an operating system patch on a virtual server, that will allow the server to be restored the fastest, is a snapshot backup.

A snapshot backup captures the state of the virtual server at a specific point in time. It is a complete copy of the virtual machine's disk file, including the operating system, applications, and data. Snapshots are quick and efficient because they only store the differences between the current state of the virtual machine and the state at the time of the snapshot. This means that the backup process is very fast and requires minimal storage space.

In contrast, a full backup is a complete copy of all data on the virtual server, which can take a long time to complete and requires a lot of storage space. Incremental and differential backups both require a previous full backup to be performed, and they only back up the changes made since the last backup. Incremental backups only back up the changes made since the last backup, while differential backups back up all changes made since the last full backup.

In summary, a snapshot backup is the best option for quickly and efficiently backing up a virtual server before installing an operating system patch, as it captures the state of the virtual machine at a specific point in time and only stores the differences between the current state and the state at the time of the snapshot.