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  • 1.  Recover data from a Delta vmdk

    Posted May 16, 2023 11:02 PM

    We have need to recover data from a snapshot with a descriptor that doesn't seem to let it boot. Is there a way to get it to boot or at least pull the data?



  • 2.  RE: Recover data from a Delta vmdk

    Posted May 17, 2023 08:08 AM
    From a previous solution to similar question: https://communities.vmware.com/t5/Backup-Recovery-Discussions/how-to-restore-data-from-delta-vmdk-without-flat-vmdk/td-p/2749690
    What's more important is the partition type and the alignment. Unless you know this, I'd suggest you do a first try with an "MBR" partition type, and a "NTFS" formatted "Basic" partition. I'd also suggest you use the default cluster size while formatting the disk, although best practices recommend another cluster size for SQL server.

    The good news is that chances to restore files are high due to the size of the delta file, which almost reaches the virtual disk's provisioned size.

    Here are the steps:

    enable SSH on the ESXi host, and login via e.g. putty
    go to the folder with the delta file: cd /vmfs/volumes/<datastore-name>/sql2008-erp
    make sure that neither sql2008-erp.vmdk nor sql2008-erp-flat.vmdk already exist!!!
    create a new virtual disk: vmkfstools -c 41945715k sql2008-erp.vmdk -d thin
    attach the newly created virtual disk to a helper VM, and format it as mentioned above
    shut down the helper VM
    run cat sql2008-erp.vmdk and make note of the "CID" value
    replace the "parentCID" value with the above noted value in the attached sql2008-erp-000002.vmdk file
    upload this file to the VM's folder on the datastore
    edit the helper VM's configuration (.vmx) file, and replace sql2008-erp.vmdk with sql2008-erp-000002.vmdk
    reload the .vmx file as explained in Reloading a vmx file without removing the virtual machine from inventory (1026043) | VMware KB
    create another snapshot to ensure that the data in the delta file doesn't get modified
    power on the VM and check the result
    Note:

    To edit the attached .vmdk file, either use an editor which can handle unix line breaks, or upload the file first, and then use the vi editor to edit it. If you are going to use WordPad, make sure that you select .txt as the file format when you save the file!!!


  • 3.  RE: Recover data from a Delta vmdk

    Posted May 17, 2023 09:12 PM

    As a first step, create a file listing to see which files are present in the VM's folder.
    To do this please run ls -lisa > filelist.txt, and attach the resulting filelist.txt to your next reply.

    André