Hyper-V Replica Feature Overview
Published: February 29, 2012
Updated: April 27, 2015
Applies To: Windows Server 2012
In Windows Server 2012 the Hyper-V role introduced Hyper-V Replica as a built-in replication mechanism for virtual machines. Hyper-V Replica can asynchronously replicate a virtual machine in a primary site to a replica virtual machine in a secondary site.
Here we see a primary site with a Hyper-V host server running Windows Server 2012 or later and a secondary site with another host server. Virtual machines on the primary site replicate to machines on the secondary site, enabling workload continuity and recovery when outages occur.
Resilience—Provides workload resilience with replication between branch offices or regional sites in different geographical locations for small to medium businesses.
Scalability—Replication can be scaled and automated by deploying it together with the Azure Site Recoveryservice. When you integrate with this service you can replicate between on-premises sites or between an on-premises site and Azure.
Lower costs—Lowers the cost-of-ownership by providing a storage-agnostic and workload-agnostic solution that replicates efficiently, periodically, and asynchronously over IP-based networks across different storage subsystems and across sites. It doesn’t rely on shared storage, storage arrays, or other software replication technologies.
Recovery—Allows quick recovery with minimal downtime and the ability to run workloads from a secondary site when outages occur.
Because Hyper-V Replica is so simple and flexible, it can be used in a wide variety of potential scenarios of varying complexity. Some examples include:
Head office and branch office
In this scenario, there are two sites: a main head office and one or more branch offices in different physical locations. Taking advantages of virtualized workloads, Hyper-V Replica can be used to provide disaster recovery support for the branch offices. The servers at any of the sites can be clustered or standalone.
For this situation, day-to-day operations would run on the virtual machines running on primary servers at the various branch offices. Each branch office would have a Replica server standing by at the head office to take over the workload in the event that the primary server must go offline for any reason.
In Windows Server 2012 R2, you can extend this scenario further using extended replication. Each branch office would have its Replica server located nearby, which then uses extended replication to send changes to an extended Replica server back at the head office.
This scenario can be scaled up to involve large datacenters with many servers without requiring any different management activities with respect to Hyper-V Replica.
Cloud service provider
In this scenario, the hosting provider sets up a Replica server at their datacenter which receives replication data from a number of primary servers running virtualized workloads on the premises of their various customers. The hosting provider’s Replica server thereby provides disaster recovery capability for the customers who subscribe to it.
To assure security for the customers, this scenario would involve certificate-based authentication using certificates probably serviced by a separate certificate server owned by the hosting provider. In addition, the Trusted Group feature of Replica allows the hosting provider to segregate the replicated data from each customer, using separate storage locations and tagging to prevent data from various customers from being mixed.
Integration—Hyper-V Replica is an integral part of the Hyper-V role.
Workload-agnostic—Hyper-V Replica replicates the virtual machine so that workload that can be virtualized in Hyper-V an be replicated.
Standalone or cluster—Primary and secondary sites can be running a standalone Hyper-V host or a cluster.
Storage—No need for shared storage or specific storage technologies.
Local or remote—The primary and secondary servers can be physically co-located or widely separated geographically.
After initial replication of a primary virtual machine to a secondary, only delta changes are replicated.
Active Directory—The Hyper-V host servers don’t need to be domain members. If they are domain members they don’t need to be in the same domain.
Replication frequency—In Windows Server 2012 replication occurs every 5 minutes. In Windows Server 2012 R2, you can configure the replication frequency every 30 seconds, 5 minutes, or 15 minutes.
Testing—You can use Hyper-V Replica to test replication without disrupting your regular production replication.