Overview - Virtual Server Agent for VMware

Table of Contents


The Virtual Server Agent for VMware provides a unified protection and recovery vehicle for all virtual machine data in your vCenter. In addition to complete protection of entire virtual machines for disaster recovery, the Virtual Server Agent provides more granular backup and recovery options. Options such as customized automatic discovery, deduplication, and reporting ensure all your virtual machine data is easily traceable and retrievable whenever the need arises.

The Virtual Server Agent (VSA) for VMware may also be referred to as the Virtual Server iDataAgent for VMware.

The Virtual Server Agent (VSA) for VMware enables you to perform backup and restores and manage virtual machine data in complex virtualized environments. VSA uses vStorage APIs for Data Protection (VADP) or VMware Consolidated Backup (VCB) methods for data protection, and can operate in mixed environments with both current and older virtual machine platforms, with support for all guest operating systems supported by VADP and VCB.

The following illustration displays components and data flows for the Virtual Server Agent:

Key Features

The Virtual Server Agent offers the following key features:

Single Administration Point

The virtualization client serves a single point of administration for all proxies. The proxy computer can be any computer where Virtual Server Agent is installed. All administration activities such as backups, restores, schedules, and reports can be performed from the virtualization client.

The virtualization client also enables proxy teaming to ensure fault tolerant backups. Proxy teaming is useful when you want to back up a large number of virtual machines in a limited backup window

Automatic Protection for All Virtual Machines in a vCenter

Once you configure the Virtual Server Agent for a vCenter, all virtual machines in the vCenter are automatically selected for backup. This behavior is designed to ensure all virtual machines are backed up.

Customized Discovery

To back up specific virtual machines in a vCenter, you can define rules to automatically select virtual machines for backup. This is useful in environments where virtual machines are frequently added or removed. You can easily browse and select vCenter objects such as hosts, datastores, and resource pools to set criteria for automatic discovery.

Customized Filters

You can add filters to exclude specific virtual machines or virtual machine disks from back ups.

Detailed Reporting for Each Virtual Machine Backup

You can view a detailed report about each virtual machine backup, with information such as the name of the proxy that performed the backup, the size of backup data, and the type of backup.  When a backup job is running, you can view this information from the Virtual Machine Status tab of the View Job Details dialog box.

vCloud Backup and Restore

You can protect vCloud-specific attributes of a virtual machine and restore a virtual machine back to a vCloud.

Point-in-Time Snapshots of Virtual Machines

SnapProtect backup enables you to create a point-in-time snapshot of a virtual machine by temporarily quiescing the data, taking a snapshot, and resuming live operations. SnapProtect backups work in conjunction with hardware snapshot engines.

Block Level Deduplication

Deduplication provides a smarter way of storing data by identifying and eliminating the duplicate items in a data protection operation.

Deduplication at the data block level compares blocks of data against each other. If virtual machines contains blocks of data that are identical to each other, block level deduplication eliminates storing the redundant data and reduces the size of data in storage. This dramatically reduces the size of virtual machine backup data copies on disk and tapes.

Changed Block Tracking (CBT) is a VMware feature that can be used to optimize backups of virtual machines by reading only the allocated and modified portions of a virtual disk. CBT is automatically enabled for virtual machines running on hardware version 7 or higher.

Incremental Forever

You can perform an initial full backup and ongoing incremental backups to ensure ongoing data protection while reducing the size and time for backups and minimizing the impact on production systems. When using this approach, you can run periodic synthetic full backups to consolidate incremental backups into full VM backups without the need to touch production VMs again.


The Virtual Server Agent documentation uses the following terminology:

Proxy A physical computer or virtual machine on which the Virtual Server Agent is installed. A computer with the Virtual Server Agent installed acts as a VSA proxy to facilitate data protection and recovery operations for virtual machines.
Virtual Client A logical entity which serves as single point of administration for all proxies.
Virtual Server Agent A software module that performs backup and restore of virtual machine data.
Backupset A group of subclients which includes all of the data backed up by the Virtual Server Agent.
Subclient A logical entity that uniquely defines a unit of data to be backed up.
Discovery Searching virtual machines in the vCenter based on a specific criteria
Guest Host A virtual machine.
Guest OS The operating system running on the virtual machine (such as Windows or Linux).
Vendor The virtualization software being used (such as VMware).