Double-Take for VMware Infrastructure suite makes replicas by taking a snapshot of the VM’s disk and sending that along with the original disk to another ESX Server system. After installation, the software runs a wizard to create a new replica. The replication does not appear to run at the maximum speed of the disks or network. Unfortunately switching over to the replica uses a manual process and so requires some experience with VMware ESX Server and VirtualCenter. For example, replicas do not normally appear in the VirtualCenter hierarchy of VMs present on each server.

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