VMware vSphere Replication is a hypervisor-based, asynchronous replication solution for vSphere virtual machines. It is fully integrated with VMware vCenter Server and the vSphere Web Client. vSphere Replication delivers flexible, reliable, and cost-efficient replication to enable data protection and disaster recovery for all virtual machines in your environment.
Hypervisor-based virtual machine replication#
vSphere Replication is a deeply integrated VMware vSphere component. Any changes written to the running virtual machine's virtual disk at the primary site are captured and sent to the secondary site. At the secondary site, 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. 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 process gives administrators visibility into virtual machine protection status and the ability to recover virtual machines with a few clicks.
Configuring replication for up to 500 virtual machines by using vSphere Web Client doesn't require many steps--just the following ones:
- Select one or more virtual machines.
- Select a virtual machine.
- Define the RPO and destination for its replica.
vSphere Replication replicates the 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 are configured on a per-virtual machine basis.
Rackspace generally does not recommend setting RPO lower than 15 minutes except on a very limited basis.
Virtual machine synchronization and intelligent transfers#
vSphere Replication can do an initial full synchronization of the source virtual machine and its replica copy. After the initial full synchronization is complete, vSphere Replication only transfers altered data. The vSphere kernel tracks unique writes to protected virtual machines, identifying and replicating only those blocks that have changed between replication cycles. This process keeps network traffic to a minimum.
The virtual machine replication process is non-intrusive and takes place independently 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.