This is an archive version of the document. To get the most up-to-date information, see the current version.

Backup Architecture

In this article

The backup infrastructure in a Hyper-V environment comprises the following components:

One or more source hosts with associated volumes
Off-host backup proxy server (optional)
One or more backup repositories

One or more guest interaction proxies (optional)

The source host and the backup repository produce two terminal points between which VM data is moved. Backup data is collected, transformed and transferred with the help of Veeam Data Mover Services. Veeam Backup & Replication uses a two-service architecture — one Veeam Data Mover Service interacts with the source host, and the other one interacts with the backup repository. The Veeam Data Mover Services communicate with each other and maintain a stable connection. All backup infrastructure components engaged in the job make up a data pipe. VM data is moved over this data pipe block by block, so that processing of a single VM includes multiple processing cycles.

When a new backup session starts, Veeam Backup & Replication performs the following actions:

Veeam Backup & Replication deploys the runtime process on VM guest OSes via the guest interaction proxy (for Microsoft Windows VMs) or backup server (for VMs with other OSes).
The target-side Veeam Data Mover Service obtains the job instructions and communicates with the source-side Veeam Data Mover Service to begin data collection.
After a VSS snapshot is created, the source-side Veeam Data Mover Service copies VM data from the volume shadow copy. While copying, the source-side Veeam Data Mover Service performs additional processing — it consolidates the content of virtual disks by filtering out zero-data blocks and blocks of swap files. During incremental job runs, the Veeam Data Mover Service retrieves only those data blocks that have changed since the previous job run (note that with changed block tracking enabled, the speed of incremental backup dramatically increases). Copied blocks of data are compressed and moved from the source-side Veeam Data Mover Service to the target-side Data Mover Service.
The target-side Veeam Data Mover Service deduplicates similar blocks of data and writes the result to the backup file in the backup repository.

Veeam Backup & Replication supports a number of backup scenarios that depend on the type of repository you use and its location. For details, see Backup Repository.