VMware and Microsoft both offer virtual machine replication capabilities. VMware offers vSphere Replication as a no-cost component that is included with most vSphere licenses. Similarly, Microsoft has integrated replication capabilities in Hyper-V, with no extra licensing costs.
Both replication products are based on the use of changed block tracking. When a block is created or modified, it gets replicated to a secondary location. This allows a standby copy of the virtual machine (VM) to be retained at a secondary location.
Microsoft and VMware also allow you to adjust the replication frequency (although Microsoft introduced this capability only in Windows Server 2012 R2). The more frequently the replication cycle occurs, the less data will be lost in the event that the replica has to be activated.
On the other hand, there are also advantages to using longer replication times. Longer replication frequencies are well-suited to slow or unreliable connections because as the replication frequency increases, so too does the time-out period. This makes short losses in connectivity much less problematic. Long replication frequencies also make it easy to maintain a lagged replica that allows the organization to easily revert to a VM as it existed at an earlier point in time.
replication vs. traditional replication
Learn more about hypervisor-based replication and how it compares with other software-based replication, in this Expert Response from Brien Posey.
replication best practices for use with backup
ESG's Jason Buffington discusses replication best practices for using with backup, in this Expert Answer.
snapshot and replication in your data protection strategy
Analyst Jason Buffington of ESG discusses data protection strategies using snapshot and replication, in this Expert Answer.
This was first published in April 2014