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Windows Server backup - host level versus internal - differences

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  • Windows Server backup - host level versus internal - differences

    I have a 2012 R2 server with a 2012 R2 guest VM. If I do a backup of the VM from the host level and a backup of the VM from within the VM there seem to be some differences.





    The host level backup seems to always be a full backup - even if I have set to Fast in performance settings - whereas the backup of the same VM from within the same VM on the same day shifts from full to 'fast'.





    As well there is a difference in files transferred/backed up reported. So let's say 10 gig has been modified in the VM by users. The internal backup will accurately reflect that; however on the same day the host level will show a much greater number of data transferred.








    As the host level backup treats the VM as a single file VHD - or so I believe - does that account for the discrepancy? In other words even though only 10 gig of data has changed, somehow as far as the VHD is concerned it's a larger amount because of the way that VHD's account of their space. in a similar vein, could it be that the blocks changed on the VHD - which is what the backup I am assuming is looking at - is quite different than the amount of data actually changed - in other words if we add 10 gig of user data, the VHD will be shuffling a lot of blocks around to accommodate that/link it up so that more blocks are affected than 10 gig? Also would it make a difference if the VHD was dynamic versus fixed, VHD versus VHDX for any of this?

  • #2
    Originally posted by arlesterc View Post
    I have a 2012 R2 server with a 2012 R2 guest VM. If I do a backup of the VM from the host level and a backup of the VM from within the VM there seem to be some differences.





    The host level backup seems to always be a full backup - even if I have set to Fast in performance settings - whereas the backup of the same VM from within the same VM on the same day shifts from full to 'fast'.





    As well there is a difference in files transferred/backed up reported. So let's say 10 gig has been modified in the VM by users. The internal backup will accurately reflect that; however on the same day the host level will show a much greater number of data transferred.








    As the host level backup treats the VM as a single file VHD - or so I believe - does that account for the discrepancy? In other words even though only 10 gig of data has changed, somehow as far as the VHD is concerned it's a larger amount because of the way that VHD's account of their space. in a similar vein, could it be that the blocks changed on the VHD - Subway Surfers which is what the backup I am Psiphon assuming is looking at Hill Climb Racing- is quite different than the amount of data actually changed - in other words if we add 10 gig of user data, the VHD will be shuffling a lot of blocks around to accommodate that/link it up so that more blocks are affected than 10 gig? Also would it make a difference if the VHD was dynamic versus fixed, VHD versus VHDX for any of this?
    I'm not talking about for environments with multiple servers. But for small businesses with a single server, it seems Backup Exec is more trouble than it's worth. (i.e. After months of working fine, stops overwriting.)

    We have been using ioSafe fireproof, waterproof backup devices at these locations in conjunction with Symantec Backup Exec for a few years. (Customers who are willing to spend the money also have a redundant cloud backup or we setup a remote DFS over a VPN connection to the owners house, but not everyone is worried about having yet another copy.)

    Six months ago, we had a situation where a startup asked us to get it done for as cheap as possible and we went with cheaper routes on the software, including no Symantec Backup Exec. Just used the built in Windows Server Backup.

    Over the weekend, I was able to restore from the ioSafe into virtual machine files which I converted to VMware and put onto a loaner until we can correct the problem in their used-hand-me-down server. I was really impressed with how well it handled the situation, even though it was free.
    Last edited by singhmonal; 11th September 2018, 19:52.

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    • #3
      I am sure that, 20 months later, the OP will really appreciate the answer
      Tom Jones
      MCT, MCSE (2000:Security & 2003), MCSA:Security & Messaging, MCDBA, MCDST, MCITP(EA, EMA, SA, EDA, ES, CS), MCTS, MCP, Sec+
      PhD, MSc, FIAP, MIITT
      IT Trainer / Consultant
      Ossian Ltd
      Scotland

      ** Remember to give credit where credit is due and leave reputation points where appropriate **

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