Synthetic Backup

Synthetic backup is a backup type that creates a full backup using in-cloud data copying.

Synthetic backup is much faster due to a combination of two types of backups that provides time and network traffic savings on full backups. This combination is a chain of synthetic incremental backup and in-cloud data copying. An in-cloud data copying implies parts are copied on a cloud-side only, so backup time can be significantly less compared to backups of the same data amount from PC to cloud.

How It Works

The synthetic backup consists of three stages. These stages are as follows:

  • An Incremental Backup. This incremental backup creates a new restore point in the current generation of backups. Once a synthetic incremental backup is successfully completed, all data required for synthetic full backup is on backup storage
  • In-Cloud Data Copying. As a synthetic incremental backup is completed, a new generation is created and data from the previous generation is being copied to a new one along with data uploaded on synthetic incremental backup inside cloud storage. In-cloud copying is not supported by all storage providers. To view the supported storage list, refer to the Support for Major Storage Providers section
  • Deletion of Synthetic Incremental Data. Once a data copying in a cloud is successfully completed, a synthetic incremental backup data is deleted in a previous backup generation and a synthetic backup is considered as completed and successful.

Questions and Answers

Q: What happens if a synthetic backup is interrupted for some reason?

A: Depends on a moment when it is interrupted. In case a synthetic incremental backup was successfully completed, but in-cloud copying was interrupted for some reason (network issues, for example), a new generation will be deleted and a successful synthetic incremental backup will be considered as valid for the previous generation. If a synthetic incremental backup fails, this is considered a regular backup failure.

Synthetic Backup Applicability

Synthetic backup applies for the following backup types:

  • File-Level Backup
  • Image-Based Backup
  • VMware Backup
  • Hyper-V backup

Support for Major Storage Providers

A synthetic backup type is supported by the following storage providers:

  • Amazon S3 (except S3 Glacier Flexible Retrieval and S3 Glacier Deep Archive storage classes)
  • Microsoft Azure (except Azure Archive)
  • Backblaze B2
  • Wasabi
  • MinIO
  • S3-compatible storage (depends on storage provider)

The minimum data part size limitations for in-cloud copying imposed by storage providers can cause an appearance of some meta information in a storage

Synthetic Backup in Backup Plans

If a plan type and destination support synthetic backup, it will be switched on automatically.

If you want to run a synthetic backup by yourself:

  1. Select a backup plan you want to run a synthetic full backup for, then expand it.
  2. On the Run control, open the drop-down menu.
  3. Click Force Synthetic Full Backup.

If you change compression and/or encryption settings, a synthetic backup will not be available, so a full backup is required.