VMware Converter: Synchronize changes when perfoming P2V or V2V

VMware vCenter Converter Standalone is a great free utility to convert a physical system into a virtual one (P2V) or one virtual system into another (V2V). Starting from VMware Converter 5.0, this system supports the feature to synchronize changes between the original system and the virtual machine-copy located on the ESXi host. This feature allows to virtualize a physical server with a large amount of data on its physical disks in several steps with minimal downtime. In addition, VMware Converter and a free VMware vSphere Hypervisor (based on ESXi) can be converted into a simple system to provide disaster recovery of critical infrastructure components, periodically synchronizing changes of critical systems with their virtual counterparts.

When converting a turned-on Windows system, VMware Converter copies data from the source machine to the target VM while the source machine is running and data on it are being changed. This is an initial stage of copying. In the second step, only the changes made since the original system copy has been made. This process is called synchronization. The synchronization feature allows you to reduce downtime of an application during P2V/V2V conversion since the end application has to be disabled only during the changes transfer. Using synchronization, you can achieve reducing application downtime from several hours to 1-2 hours.

In this article, we will show how to configure synchronization between the source server (file server with 700 GB of data on its internal disks) and its virtual copy using VMware vCenter Converter Standalone 6.0 and how it works.

1. You have to download and install VMware Converter Standalone (it is better to install it on a separate server).
2. Create a new conversion task: File-> New-> Convert machine.
3. Select that you need to convert a running system (Powered-on machine), specify its name/IP address, OS type and account, as well as the password of user having administrative privileges.
4. VMware Converter connects to the specified server and installs VMware vCenter Converter Standalone Agent (vmware-converter-agent) on it
5. Then you will be prompted to specify the name of the ESXi server (or vCenter server), on which the virtual machine will be created, and credentials to access it
6. We will be prompted to specify the name of the virtual machine, its location, host, a disk storage and version of the virtual machine hardware
7. Then you will have to select the disks of the target system, which have to be copied, the settings of memory and CPU, etc. We are most interested in the settings of the Advanced section.
8. We are going to convert the system into VM in two steps: the initial one, when initial conversion is performed, and the final one, when changes are synchronized since the data has been copied for the first time.
9. Check Synchronize change. Select when the next synchronization will be performed. Necessarily (!!) uncheck Perform final synchronization.
10. In the Post-Conversion tab, select the actions to be performed after the final synchronization. We want to automatically turn on the created VM (Power on destination machine), turn off the source server (Power off source machine), install  VMTools, etc.
11.  Now you only have to start the initial phase of the P2V conversion and wait till it is completed.
    Note: In this case, the conversion of the physical file server with 700 GB of data took about 15 hours.
12. After the initial conversion is over, we can perform manual synchronization. To do it, select the task in VMware Converter and then click Synchronize in the shortcut menu.
    Note: VMware Converter installs special “bitmap driver” (bmdrvr service ), which tracks changes in the system since the last synchronization.
13. In the wizard window, select the synchronization to be run immediately, and run the final synchronization after it is over. To ensure that users can not edit files on the server during the final synchronization, you can temporarily stop the file service.
14. The final synchronization took about an hour, during which the changes on the source machine has been replicated to the VM. After that, the old server has been automatically shut down, and the new VM  turned on.
15. You only have to perform the final configuration of the VM (remove hidden network interfaces and old device drivers, assign IP addresses to new network interfaces, etc.), and the virtual machine is ready for operation.

During synchronization of changes, the vSphere server will create some snapshots on the target machine, which allow to roll back to any stage of synchronization if necessary (in this case the logic of VMware Converter will be broken).