VMware P2V Conversion Fails with BlockLevelVolumeCloneMgr: Detected a write error during the cloning of volume …. Error 37409



After many successful P2V conversions I ran into this one 2008 R2 server that caused me a lot of grief. The C: drive would clone, but the remaining three drives would fail with this, or a similar, message “BlockLevelVolumeCloneMgr: Detected a write error during the cloning of volume …. Error 37409”.

Given the server was a production SQL server with over 700 GB of data, the conversion and cut-over had to be scheduled over the weekend. We’re running vSphere Enterprise 5.1. After several attempts with various versions of the converter: 5.0.1, 5.1.0, 5.1.2, where the converter would complete drive C: then fail, I decided to give Converter 6.1 a try. This time the conversion completed, but the final sync failed. So I finally tried a few recommendations I found on VMware forums. Here’s what worked for me:

  1. Disable SSL on VMware Converter.
    • http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2020517
    • This reduced the conversion time from 20 hours to 5.5 hours
  2. Stop the SQL service before starting the conversion.


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