One of the benefits of virtualization is the simplification of backup and recovery down to the “bare metal.” Bare metal recovery used to be a complex process requiring extremely similar if not the same hardware to restore to, or special software to make sure that the differing hardware didn't cause problems with restoring the operating system. That's largely a non-issue when restoring workloads back into the virtualized environment.

The trend in virtualized environments is agent-less backup which interacts with the hypervisor to quiesce the workload, take a hypervisor snapshot, and backup that snapshot. Essentially, the vSphere, Hyper-V, or XenServer native tool installed on the workload acts as the agent to quiesce the workload for an application-consistent snapshot. VMware vSphere, Microsoft Hyper-V, and Citrix XenServer have native APIs to allow backup software to interact with the hypervisor and workload agents for this process.

There are several software tools that focus on interacting with the APIs in question and adding their own value propositions as well.

Veeam Backup and Replication

• http://www.veeam.com/vmware-esx-backup.html
• vSphere and Hyper-V
• Virtual workloads only
• 5 minute Recovery Point Objective
• Automatic backup verification
• Object-level restore
• Free Edition available

Unitrends

• http://www.unitrends.com/
• Available as an appliance or a virtual appliance
  • Appliance Family
    http://www.unitrends.com/products/appliance-family.html
    
  • Unitrends Enterprise Backup virtual appliance
    http://www.unitrends.com/unitrends-enterprise-backup.html
• vSphere, Hyper-V, and physical hosts
• 15 minute RPO with the Appliance and as little as 60 seconds with UEB
• Appliance can be used as a DR host, booting backup images
• UEB gives the first four workloads to be backed up for free

PHD Virtual Backup and Replication

• http://www.phdvirtual.com/solutions
• vSphere and XenServer platforms

AppAssure Replay (bought by Dell Feb 2012)

• http://www.appassure.com/server-backup-and-replication/
• Provides a single product for both physical and virtual workloads.
• vSphere, XenServer, and Hyper-V platforms
• Automatic backup verification.
• Both Bare Metal, application object, and file level restore.
• 5 minute Recovery Point Objective

QuorumSoft Alike

• http://www.quorumsoft.com/
• XenServer 5.5+, XCP 1.0+
• Global, block-level deduplication
• File level restore