Before installing an OS patch on a virtual server, which backup type allows the fastest restoration?

A snapshot provides an almost instantaneous way to restore a virtual server to its previous state before an OS patch is applied. When a snapshot is created, it captures the entire state of the virtual machine, including the disk, memory, and settings at that specific moment in time. This allows you to quickly revert to that state if necessary, making restoration very efficient.

In contrast, while full backups encompass all data and settings, they take longer to restore because all data must be copied back to the server. Incremental and differential backups also complicate the restoration process since these types require a full backup in addition to the previous backups to fully recover the system. Thus, using a snapshot is typically the fastest method for restoring a system to its pre-patch state, allowing for minimal downtime and rapid recovery in case of issues arising from the patch installation.