vSphere Replication provides flexible recovery options, ensures consistent application and virtual machine data, and it integrates with the VMware product stack. vSphere Replications allows you to:

• Customize the recovery point objective (RPO) from 5 minutes to 24 hours
  
• Use multiple point-–in-time (MPIT) recovery to revert to previous known states
• Protect up to 2,000 virtual machines per vCenter Server environment
• Use Microsoft Volume Shadow Copy Service (VSS)
• Use Linux file system quiescing
• Automate cross-site disaster recovery with VMware Site Recovery Manager
• Protect and recover virtual machines on VMware vSAN
  
• Protect and recover virtual machines on vSphere Virtual Volumes datastores

vSphere Replication is a hypervisor-based replication solution that operates at the individual virtual machine disk (VMDK) level, allowing replication of individual virtual machines between heterogeneous storage types supported by vSphere. Because vSphere Replication is independent of the underlying storage, it works with a variety of storage types including VMware vSAN, vSphere Virtual Volumes, traditional SAN, network-attached storage (NAS), and direct-attached storage (DAS). This allows you to:

• Use differing storage technologies at linked sites, such as in SAN-to-vSAN and Fibre Channel (FC)-to-Internet Small Computer System Interface (iSCSI) arrangements
• Repurpose older storage at the recovery site to reduce cost
• Use secondary storage only for protected virtual machines, not the entire environment

vSphere Replication copies only changed data to the recovery site to lower bandwidth utilization, improve network efficiency and enable more aggressive RPOs than a manual, full-system copy. With vSphere Replication, you can:

• Utilize a “seed copy” of virtual machine data for the initial synchronization to reduce the amount of time required to create the initial copy
• Ensure efficient network utilization by tracking changed disk areas and replicating only those changes
• Optionally enable data compression to further reduce network bandwidth consumption

vSphere Replication is a deeply integrated VMware vSphere component. It is a robust hypervisor-based virtual machine replication engine. Changed data in virtual machine disks for a running virtual machine at a primary site is sent to a secondary site. There, the changes are applied to the virtual machine disks of the offline copy (replica) of the virtual machine.

vSphere Replication includes an agent built into vSphere and one or more virtual appliances deployed using vSphere Web Client. The agent tracks and sends changed data from a running virtual machine to a vSphere Replication appliance at a remote site; the appliance then adds the replicated data to the offline replica copy for that virtual machine. The vSphere Replication virtual appliance also manages and monitors the replication process. This gives administrators visibility into virtual machine protection status and the ability to recover virtual machines with a few clicks.

It’s easy to configure replication for up to 2,000 virtual machines using vSphere Web Client: select one or more virtual machines, right-click on a virtual machine, and define the RPO and destination for its replica. 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. RPOs range from 5 minutes to 24 hours and can be configured on a per-virtual machine basis.

vSphere Replication can do an initial full 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. A seed copy is manually created and placed at the recovery location using any mechanism the administrator chooses, such as offline copying, FTP, an ISO image or a virtual machine clone.

After the initial full synchronization is complete, vSphere Replication will transfer only changed data. The vSphere kernel tracks unique writes to protected virtual machines, identifying and replicating only those blocks that have changed between replication cycles. This keeps network traffic to a minimum and allows for aggressive RPOs.

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