What is hypervisor-based replication, and how does it compare with other software-based replication?
Hypervisor replication is a technology that automatically creates and maintains replicas of virtual hard disks or entire virtual machines (depending on the platform that is being used). This is different from traditional backups because the replication process is ongoing as opposed to traditional backups that normally run at scheduled intervals.
Generally speaking, hypervisor replicas are more of a disaster recovery solution than a backup replacement. If a host server or a storage array were to be damaged, resulting in the loss of virtual machines, then replicas could be used to replace those virtual machines. However, replicas are not good for performing item-level restoration of files, folders, applications, etc. The reason for this is that replicas usually mirror the contents of the primary host server.
If a file has been erased from the primary copy of a virtual machine, that file will be removed from the replica as well. Some replica solutions allow for the creation of snapshots (which make point-in-time restorations possible), but snapshots are not a good substitute for a traditional backup.
This was first published in November 2012