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RCT queries RRS feed

  • Question

  • Hi, we are trying to use the RCT . Few questions related to it:

    1. the query WMI GetVirtualDiskChanges or VHD QueryChangesVirtualDisk returns access_denied error for the full backup. Any idea on what is best to perform full backup ?

    2. We tried the below procedure and found to get the corrupted disk.

      1. Create production snapshot using WMI
      2. then we manually Copied the vhdx file to some other directory (say c:\temp\vm1)
      3. Created reference point (say, RCT_id1).
      4.Create snapshot again
      5. Run in GetVirtualDiskChanges query to get changed blocks since RCT_id1
      6. Read the blocks (offset/length) - (seek and read) to get the data to buffer.
      7. Write the buffer to c:\temp\vm1\ (saved in step 2) - overwrite
      8. Open the c:\temp\vm1\vm1.vhdx =====> This is corrupted.

    Any help here is appreciated

    Saturday, August 8, 2020 9:19 AM

All replies

  • Hi Experts, Are the above mentioned step incorrect ?

    >> Does the  GetVirtualDiskChanges does not return the offset from the start of the disk ? I mean does it exclude VHDX metadata and provide in offset ?

    >> As per the VHD reference guide, the ByteOffset retuned as part of QueryChangesVirtualDisk function will be from the start of the  disk (From VHD reference buid: The distance from the start of the virtual disk to the beginning of the area of the virtual disk that has changed, in bytes.). 

    Is my understanding correct. Please confirm

    Monday, August 10, 2020 9:25 AM