What Is Synthetic Backup?

Over the years, the global business community has experienced a dramatic increase in data which needs to be processed, stored, and protected. Considering the fact that data protection is of utmost importance, companies should implement best practices to secure themselves against all types of disasters and properly react in case any of these occur.

One of the best practices that ensure effective and low-cost data protection is to regularly back up your data, in particular, the VM data. There are several backup types: full, incremental, and differential backups, which are the traditional ways to perform backup, and forever-incremental and synthetic backups, which emerged relatively recently. In this article, we will talk about the synthetic backup and its advantages over the traditional backup types.

What Is Synthetic Backup and How it Works?

All legacy backup solutions require following the traditional approach to VM backup and, thus, performing full backups at least once in a while. However, this approach to backing up VM data has its drawbacks: creating a full backup takes a lot of time and produces extra load on both the infrastructure resources and the network, and the final full backup of a virtual machine is quite large and needs plenty of space in the backup repository to be stored.

To get rid of the abovementioned shortcomings of the traditional backup, the synthetic full backup was invented.

The principle of performing the synthetic backup is, that unlike the traditional approach, we need to create a full backup of the VM only once. After that, we will create forever-incremental backups on a daily basis, and these increments will contain only changes made to the source VM since the previous backup. Actually, we have both the initial full backup and all of the successive changes, so it makes no sense to create a full backup once again. To get a synthetic backup, we can, roughly speaking, read both the initial full backup and all of the incremental backups with changes stored in the vSphere backup repository and finally synthesize these data into a backup, which will be identical to the full backup created in a traditional way and fully reflect the state of the respective VM at the particular point in time.

Why Synthetic Backup?

The synthetic approach to creating backups has a set of advantages. These are:

  • Synthetic backups reduce the load on the source server, because synthetic backups are created in the backup repository, but not in the source server;
  • Synthetic backups reduce the load on the network, as the amount of data transferred from the source server to the backup repository is significantly decreased;
  • The VMs can be easily and quickly restored anytime you need.

Full Synthetic Data Storage with NAKIVO Backup & Replication

Being a newer VM backup solution, NAKIVO Backup & Replication uses the synthetic approach to creating and storing VM backups. After the initial full backup, all jobs are forever-incremental. Using the CBT and RCT technologies, the product tracks changed data blocks made to the VM and transfers only these blocks to the backup repository. After each backup job run, NAKIVO Backup & Replication creates a recovery point, which is essentially a set of references to data blocks stored in a single pool in the backup repository. These recovery points can be used to restore the necessary virtual machine as of a particular moment in time.

 Synthetic Backup

Therefore, there is no need to create periodic full backups, as the data in the backup repository is stored using the so-called “full synthetic mode”, which eliminates the need for backup transformation.

The full synthetic mode gives NAKIVO Backup & Replication advantage over the products applying the traditional backup approach, because:

    • All data blocks are stored only once, are unique, and can be referred to by multiple recovery points.
    • Synthetic backups are substantially faster, as you don’t need to run the backup, and each recovery point “memorizes” data blocks that should be used for an entire machine restoration.
    • Synthetic backups are much safer in comparison with traditional backups. If you lose a data block or an increment in a chain, NAKIVO Backup & Replication will provide you with all recoverable increments.
    • As each recovery point already “knows” which data blocks should be used for VM recovery, the recovery process will run much faster.


The synthetic backup is a good alternative to backing up your VM data using the traditional backup types. It facilitates and speeds up VM backup and recovery, improves RPO and RTO, unloads your infrastructure resources and network, and saves you a lot of time and money.