Conducting hot P2V migrations with VMware Converter

Hot cloning is more burdensome than cold, because the servers are still online. But this step-by-step guide to hot cloning helps you circumvent some of the hassle.

Preparation is the key to help prevent physical-to-virtual, or P2V, migration failures with VMware Converter. In...

this tip, I'll give you step-by-step instructions on how to prepare your server for a hot clone. (Most of these steps can be skipped with cold clones, as the server's OS is not running during the conversion.)

In a previous installment of this series, we talked about what VMware Converter will do, hot cloning (which is when you make a P2V migration while the server is still online) vs. cold cloning (which is when you migrate after the server is offline), and which servers you should probably stay away from when using VMware Converter.

Below are the steps you should take to prepare your server for conversion.

  1. Install the Converter application on the server being migrated. If you are using the Enterprise version you can do this remotely, but my preference is to install Converter direcly on to the server a potential complication caused by introducing another PC in the conversion process. If you have many machines to convert this is not always practical. The Converter application consists of two parts, the Agent component (Windows service) and the Manager component (front end GUI). If you are running this on the server directly you need both components. Otherwise if you are running it remotely only the Agent component is needed.

  2. Once you install the application on the server a reboot will be required if the server OS is Windows NT 4.0 or 2000. This is because a special driver is installed for the cloning process on those OS's, Windows XP and 2003 utilize the Volume Shadow Copy service instead. Also, it's best to use a local administrator account when logging into the server to install the application.

  3. The following Windows services must be running for Converter to work properly: Workstation, Server, TCP/IP Netbios Helper and Volume Shadow Copy (Windows XP/2003, can be set to manual, just not disabled). Also, disable Windows Simple File Sharing if your source server is running Windows XP.

  4. Make sure the VMware Converter Windows service is running.

  5. Ensure you have at least 200 MB free on your source server's C drive. Mirrored or striped volumes across multiple disks should be broken; hardware RAID is OK since it is transparent to the operating system. Converter sometimes has issues converting dynamic disks, if you experience problems with them, then cold clone instead.

  6. Disable any antivirus software running on the source server.

  7. Shutdown any applications that are not needed on the server.

  8. Run chkdsk and defragment your source server's hard disks.

  9. Clean-up any temporary and unnecessary files on the source server. The less data that needs to be copied the better. This only applies when utilizing file level cloning (more on that later).

  10. Keep users off the server while cloning. Disable remote desktop and any shares if possible.

  11. Ensure required TCP/UDP ports are opened between the source server and VirtualCenter (VC) and VMware ESX. Even if you select VirtualCenter as your destination, the ports still need to be opened to the ESX server you choose. The source server first contacts VC to create the VM and then ESX to transfer the data to. Required ports are 443 and 902 (source to ESX/VC) and 445 and 139 (converter to source and source to Workstation/Server). These ports need to be opened on both OS firewalls and any network firewalls sitting between your source and destination servers.

  12. Ensure your network adapter speed/duplex matches your physical switch setting. This can have a dramatic effect on your conversion speed. When cold cloning it's best to set your physical switch port to Auto/Auto since this is what the Windows PE ISO will default to.

  13. If importing a VM or physical image the Windows version of the server running Converter must be equal to or greater then the source. So, if your source is Windows 2003, the server running Converter cannot be Windows 2000.

  14. For cold cloning, the minimum memory requirements is 264 MB (will not work with less then this amount), the recommended memory is 364 MB. Converter also utilizes a RAM disk if you have at least 296 MB of memory available.

Making the conversion
With these steps complete, we're ready to get started. Start the Converter Manager application and click the Import Machine button to start the Converter Wizard. Select your Source server, in this example we will choose Physical Computer. Select This Local Machine if running Converter on the source server, otherwise enter the hostname/IP and login information of the server to be converted. At the Source Data screen you have the option to select your disk volumes and re-size then larger or smaller if needed. Make sure you do not select any small utility partitions created by your hardware installation. What you decide here will determine which disk cloning method is used to copy your source data. If you do not change your drive sizes or increase them, then a block-level clone will be performed. If you decrease the size of your drives by any amount then a file-level clone will be performed instead.

When a block-level clone is performed, data is transferred from the source server disk to the destination server disk block-by-block. This method is faster but results in more data being copied (even empty disk blocks are copied). When a file-level clone is performed, data is instead transferred file-by-file, which is slower but results in less data being copied. So if you only have 5 GB of data on a 40 GB drive, then only the 5 GB is copied. It's a trade-off between the two methods between faster transfer speed versus reduced data size which often results in about the same time to copy the data. One potential caveat with the file-level copy is if you have a server with a huge amount of small files, it can take days to copy the data, and will sometimes fail. I experienced a server with 200,000+ 2 K files in one directory which brought the conversion to a crawl. Once I removed these files it completed in a few hours.

Next choose your destination server which is typically VirtualCenter (VC)/ESX. If you have a VC server managing a destination ESX server, it is best to choose the VC server first. Continue entering a VM name, host and datastore; at the Networks screen you can select one or more NIC's and networks to connect to.

My preference is to first connect the VM to an Internal Only vSwitch so it is isolated from the source server and I can power it on while the source server is still up. Once I verify that the newly created VM is functioning properly and I go through the post-clone procedures, I shutdown the source server and move the VM to the same network that the source server was on.

Finally select whether or not to install VMware Tools, enter any OS customization if necessary, select whether or not to power on the VM right after the conversion completes and click the Finish button to start the conversion process. Once the conversion starts you can monitor the progress in the task progress window.

In our final part to this series we will discuss troubleshooting failed conversions and post-conversion procedures.

ABOUT THE AUTHOR: Eric Siebert is a 25-year IT veteran with experience in programming, networking, telecom and systems administration. He is a guru-status moderator on the VMware community VMTN forums and maintains, a VI3 information site.

This was first published in March 2008

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