Architecture of Resiliency Platform Data Mover
When you want to recover VMware virtual machines from an on-premises data center to an on-premises data center then the replication technology used is Resiliency Platform Data Mover with VMware vSphere APIs for I/O Filtering (VAIO) framework. The framework provides an I/O filter for replication that has been certified by VMware. The filter runs inside an ESXi server and intercepts I/O requests moving between a guest operating system and virtual disks. For more information on VMware API I/O filtering framework, refer to VMware documentation.
Resiliency Platform Data Mover deploys a user-land module, called vtstap, on the ESXi host where the protected virtual machines are running. This module is built using the VMware VAIO APIs to intercept and replicate I/Os from the virtual machines.
After Veritas Resiliency Platform Data Mover filters I/Os in the user land of the ESXi host where virtual machines are running, the I/O goes through the following path within the Replication Gateway at the source data center before it is replicated to the target data center.
Each Replication Gateway includes five daemons that run when replication is enabled:
I/O receiver
Continuously receives the virtual machine I/Os that were tapped and sent by the vtstap module in the ESXi host where virtual machines are running.
Transceiver
Transfers and receives data over the WAN link periodically.
Applier
Applies the data to the storage after it is received on the target gateway.
Scheduler
Manages and schedules data transfer between gateways.
Engine
Maintains the state of replication and also coordinates with all other components.
The virtual machines on the target (recovery) data center are provisioned only when a disaster recovery operation (such as recover) is run. The disaster recovery operation then can bring the virtual machines online in the recovery data center. This avoids unnecessary resource utilization and accounting when the workload is running in the other data center.
To use Veritas Resiliency Platform Data Mover, the source Replication Gateway and the target Replication Gateway are linked together into a Replication Gateway pair. This establishes the replication channel between the source and the target data centers. You can choose to encrypt the communication between gateways, unless you are using a dedicated VPN link.
