The concept of immediate recovery is relatively simple - the ability to run a virtual machine directly from the backup of this virtual machine - but the possibilities offered by such a simple concept are virtually limitless, which explains why it is considered one of the most important advantages of backup and recovery by many years.
Before the immediate recovery came, all the restorations were basically the same, starting with the way the backups were stored - in some kind of container or image. Prior to commercial backup and recovery software, they were stored in formats such as tar, CPIO or Dump.
More information about backup and recovery:
Backup and archive: why you should know the difference
How to choose a method for backing up data off-site
Tape and disk storage: why the tape is not dead yet?
The right backup level saves time, bandwidth and space
Most commercial backup products choose different formats, usually proprietary, for storing backups, but the result was always the same; backups must first be restored to be useful. Restore was the reverse of a backup; opened the backup container, extracted the appropriate files and copied them to the appropriate location.
The path to immediate recovery began with some backup companies that decided to store their backups in such a way that they were directly accessible; they were no longer trapped in the container, reserved or not. This made it possible to mount the file system backup directly instead of restoring it first. For example, some backup systems allowed direct access to the VMDK backup as VMDK, which meant that you could run the virtual machine using VMware.
What began as accelerating the recovery of individual files quickly turned into something more. For the first time, customers could easily check if their virtual machine backup was good by simply asking the backup system to install the backup as a real system. He broke a basic axiom that you never knew if your backup was good until you restore it. It definitely changed the game.
