Reduce Bandwidth Needs

vSphere Replication, VMware’s proprietary replication engine, copies only changed blocks to the recovery site. This approach lowers bandwidth utilization and enables more aggressive recovery point objectives (RPOs) than manual, full-system virtual machine replication. With Replication, you can:

  • Leverage a “seed copy” of virtual machine data during initial synchronization.
  • Ensure efficient network utilization by tracking changed disk areas and only replicating deltas.

Eliminate Storage Lock-In

vSphere Replication is the only hypervisor-based replication solution, that operates at the individual virtual machine disk (VMDK) level, allowing replication between datastores hosted on any storage.

  • Repurpose older storage at protection site.
  • Allow for differing storage technologies at opposite sites (e.g. SAN to NAS, FC to iSCSI).
  • Use secondary storage only for protected virtual machines, not the entire environment.

Build Flexible Disaster Recovery Configurations

Ensure consistent application and virtual machine data with a single click when configuring a virtual machine for replication.

  • Integrate automatically with Microsoft’s Volume Shadow Copy Service (VSS) to ensure consistent recovery copies.
  • Leverage flexible RPOs of 15 minutes to 24 hours.
  • Control virtual machine replication via VMware vCenter Server.
  • Scale to hundreds of virtual machines per cluster.
  • Use multiple point–in-time snapshots to revert to previous known states.

Technical Details

Hypervisor-Level Virtual Machine Replication

Replication is a deeply integrated VMware vSphere component—it’s the industry’s only true “hypervisor-level” virtual machine replication engine. Changed blocks in the virtual machine disk(s) for a running virtual machine at a primary site are sent to a secondary site. There, they are applied to the virtual machine disks for the offline (protection) copy of the virtual machine.

Agent-Based Replication Management

vSphere Replication includes an agent inside the core vSphere installation package on each host, plus a set of virtual appliances that are deployed from the management interface. The agent sends changed data from a running virtual machine to the appliance at a remote site; the appliance then adds the replication to the offline disk files for that virtual machine. The appliance also manages the replication process, giving administrators visibility into virtual machine protection status as well as the ability to recover virtual machines with a few clicks.

Adjustable Recovery Point Objectives

It’s easy to configure replication for up to 500 virtual machines via the standard vCenter Server management interface: simply right-click on a virtual machine and select the destination for its replica. The process includes setting an RPO to define how old each virtual machine copy is allowed to get. vSphere Replication will then replicate data to meet the RPO at all times, ensuring that virtual machine content never ages past its defined replication policy.

Virtual Machine Synchronization and Seed Copies

vSphere Replication will do an initial synchronization of the source virtual machine and its replica copy. If desired, a seed copy of data can be placed at the destination to minimize the time and bandwidth required for the first replication. A seed copy of a virtual machine consists of a virtual machine disk file that can be positioned at the target location through nearly any mechanism. A seed can be manually created or copied into place by any mechanism the administrator chooses, such as offline copying, FTP, “sneakernet” or even an ISO or virtual machine clone.

Intelligent Transfers

After baseline synchronization is complete, vSphere Replication will transfer only those blocks of data that have changed. The vSphere kernel tracks unique writes to protected virtual machines, identifying and replicating only those blocks that have had unique writes during the pre-set RPO. This keeps network traffic to a minimum and allows for aggressive RPOs. Unique data only requires sending once. Only changes will be replicated and sent to the target location’s vSphere Replication appliance.

Non-Intrusive Replication

The virtual machine replication process is non-intrusive and takes place irrespective of the operating system. It is transparent to protected virtual machines and requires no changes to their configuration or ongoing management.

Hypervisor-level virtual machine replication diagram

Changed blocks

Hypervisor-level virtual machine replication diagram

Replication intelligent transfers diagram

Data flow of replication from vSphere agent to VR Appliance

Replication intelligent transfers diagram