VMware Converter 5.0 incremental synchronization feature
November 22, 2011 1 Comment
When performing a conversion of a physical server to a virtual one (P2V) several tools are available. VMware has been offering the free to use VMware Converter for a long time. Novell has a commercial solution named PlateSpin Migrate.
PlateSpin Migrate used to have a unique feature which was able to create a virtual machine and transfer all the data while the source server remains online. Then, during a maintenance window applications on the source server are stopped and the changed data since the initial transfer (or delta) is tranfered (synchronization).
The synchronization feature reduces downtime of applications since only during delta transfer the application needs to be shutdown. Good for the end-users and good for the staff performing the conversion during off hours. Instead of waiting lots of hours to complete the P2V data transfer, you now can be ready in less than an hour (after post conversion tasks like removing management software etc).
Since the release of VMware Converter 5.0 the tool has a synchronization option like Migrate is offering. I used both Migrate and Converter and must say Converter works much easier. Migrate needs to prepare the target server and can have issues. Converter simply performs a P2V conversion and the admin selects to synchronize changes. Synchronization can either be immediately or scheduled. Do not select ‘Perform final synchronization’ when you run the P2V job for for the first time.
A synchronization run can simply be started by clicking on the job used for the initial P2V and select ‘synchronize’. A click on Next and Finish and off you go. How simple is that!
As PlateSpin Migrate works with a helper VM this has much more potential issues than the vCenter Server API communication which Converter is using.
The only feature missing in Converter is the ability to automatically configure the IP-configuration of the target server. This is something which can be automated by PlateSpin Migrate. Also Migrate can be used for other hypervizors than VMware alone.
Scheduling synchronization only works on vCenter or ESX(i) server 4.0 and above. For older ESX/VC and all Workstation/Fusion/Player only one-time immediate synchronization is supported.
Converter installs the so called “bitmap driver” which is used to track changes on the source between the last and the current synchronization. The idea is to transfer only changed sectors thus minimizing the synchronization time. Since bitmap driver once started cannot be stopped, it is set to manual start rather than an autostart. The idea is if Converter needs to track changes (synchronization) – it will start the driver on demand if not running.
The bitmap driver is installed as service on the source server. The service is called bmdrvr
Keep in mind that scheduling and multiple incremental synchronizations have a limitation – the target needs to be a VC server or ESX version 4.0 and above. Converting to Workstation or ESX 3.5 does not allow scheduling synchronizations (however one immediate final synchronization is possible).