Techniques for initializing a replication relationship between virtual machines are described herein. The techniques include performing one or more pre-requisite checks, determining, at least partly in response to performing the one or more pre-requisite checks, one or more first data blocks associated with a first virtual machine that differ from one or more second data blocks associated with a second virtual machine. The second virtual machine may be instructed to send the one or more second data blocks that differ from the one or more first data blocks to the first virtual machine.