Site Recovery Manager 6.5 is deployed in a paired configuration.
Site Recovery Manager 6.5 is deployed in a paired configuration, for example. Protected site and recovery site. The Site Recovery Manager 6.5 software is installed in a Microsoft Windows server at both sites. It requires a VMware vCenter Server 6.5 at both site as well. There must be one or more vSphere hosts running version 5.0 or higher at each site.
In the above picture you can see two kind of replication. Site Recovery Manager utilizes either vSphere Replication or Array-based replication. For Array-based storage replication, Storage must be licensed and configured and the appropriate storage replication adaptor must be installed on Site Recovery Manager at each site. For vSphere replication, the vSphere Replication virtual appliance must be deployed and virtual machines to be protected by Site Recovery Manager must be configured for replication
A virtual machine can be protected with either technology though the same virtual machine cannot be protected by both.
Array-Based Replication
When using array-based replication, one or more storage array at protected site replicate data to peer storage array at the recovery site. A storage replication adaptor (SRA) is a software component required for the specific array from the storage vendor to be used with SRM for communicating with the storage array. They are there for installed on the Site Recovery Manager servers at both sites and are able to monitor and control array functions related to migration, failovers, re-protections, failbacks and tests.
vSphere Replication
To use vSphere replication requires deployment and configuration of the vSphere Replication appliance. This is installed in a separate machine (Independent of SRM). vSphere replication is on VM level and able to utilize any storage supported by vSphere so there is no requirement for similar storage arrays at either site.
vSphere Replication Agent (vRA) present on every vSphere host, It only becomes active when a protected VM is writing data.
You can use Site Recovery Manager to implement different type of recovery method from the protected site to the recovery site
Planned Migration
Planned migration can be used in case of any planned outage or annual Disaster Recovery testing. In a Planned migration, Virtual machines workloads migrate to DR site without data loss. For planned migration to succeed, both sites must be running and fully functional. At the protected site, Site Recovery Manger shuts down virtual machines cleanly and synchronizes storage. Then Site Recovery Manger powers in the replicated virtual machines at the recovery site according to a recovery plan.
Disaster Recovery
Similar to planned migration except disaster recovery does not require that both sites be up and running.