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Network Configuration Error, after export, delete, import to move VM to different drive. RRS feed

  • Question

  • running on a DELL 2950.  Using Hyper-v as a testbed platform for testing..  Have a variety of VM's, most with several snapshots of the systems in particular configurations needed for testing.  Because of the application as testbeds, I make a LOT of use of snapshots to be able to start testing at a known state, or with a known build or version of our software etc.  (way way more than I'd do with a production system obviously)..  (aside:  Hyper-V ROCKS for this kind of thing!)

    Was running low on disk, got two new 1tb drives, setup as a mirror for a new F: drive.

    To move machines, I started with those that had been created 'natively' instead of via export-import cloning  because the snapshots and VM's are spread out over the drive, and it's difficult to tell how much space a particular VM is using.  (not a problem for exported->imported VM's of course, where everything is under one neat tree)

    So for those VM's I did the following (mostly with HVM from my vista workstation)
    1.   Exported from c:  to a new dir on F:
    2.   verified the export looked good by checking the files via remote desktop to the host
    3.   used HVM to delete the snapshots, from bottom up, one by one
    4.   Then deleted the VM, and manually deleted the VHD from the C: drive.
    5.   Imported the VM from it's new home on the F: drive, re-using the ID's since I was basically just moving the machine.

     This all seemed to go well, but for at least one of my VM's, when I tried to power it back up, it would not go.  checking settings for all the snapshots, and the 'now' instance, I see configuration errors regarding the network adaptor.

    Any idea why this happened?  I didn't change any network settings anywhere. 

    The problem is fairly easy to fix, but since I cannot alter the network settings for the snapshots, it means I have to apply each snapshot in turn, change the settings for the 'now' instance, and then re-save the snapshot..  Of course doing that for a snapshot tree destroys the tree and flattens it out, which is a bit of a PITA for me in terms of knowing the 'heritage' of each snapshot.


    Is there a way to 'fix' the snapshots without having to apply, change settings, and re-create the snapshot?  so I can keep the tree intact?
     
    --Chuck
    Wednesday, March 25, 2009 6:23 PM

Answers

  • Hi Chuck,

    Unfortunately this is a known limitation with import / export and snapshots.  We do not correctly handle the network configuration of snapshots.  The reason for this is that in our architecture snapshots are always "read only" and our networking implimentation is not flexible enough to adapt.

    This is certainly something we want to address in the future - but I cannot make any statements / promises about when it will be addressed.
    Cheers,
    Benjamin Armstrong
    ============================
    Windows Virtualization
    Senior Lead Program Manager

    This posting is provided AS IS with no warranties, and confers no rights. You assume all risk for your use.
    • Proposed as answer by Vincent Hu Friday, March 27, 2009 6:17 AM
    • Marked as answer by Vincent Hu Monday, March 30, 2009 3:39 AM
    Wednesday, March 25, 2009 6:31 PM

All replies

  • Hi Chuck,

    Unfortunately this is a known limitation with import / export and snapshots.  We do not correctly handle the network configuration of snapshots.  The reason for this is that in our architecture snapshots are always "read only" and our networking implimentation is not flexible enough to adapt.

    This is certainly something we want to address in the future - but I cannot make any statements / promises about when it will be addressed.
    Cheers,
    Benjamin Armstrong
    ============================
    Windows Virtualization
    Senior Lead Program Manager

    This posting is provided AS IS with no warranties, and confers no rights. You assume all risk for your use.
    • Proposed as answer by Vincent Hu Friday, March 27, 2009 6:17 AM
    • Marked as answer by Vincent Hu Monday, March 30, 2009 3:39 AM
    Wednesday, March 25, 2009 6:31 PM
  • OK, well at least it's easily enough repaired even if it is a hassle.   so no way to like change values in the XML files or anything? 

    Would there have been a better way for me to go about moving these machines that would not cause this issue?  I have several more that we should relocate to better balance things between the drives in this system.

    Thanks for your help here and your blog BTW..  a lot of what I know re hyper-v comes from you.
    --Chuck
    Wednesday, March 25, 2009 6:49 PM
  • Chuck:

    I would just like to confirm one datapoint: are you running v1 of Hyper-V or the Beta of Server 08 R2 Hyper-V?

    Thanks,
    Soumya.
     
    This posting is provided "AS IS" with no warranties, and confers no rights
    Wednesday, March 25, 2009 9:43 PM
  • Not running a beta.   Should be the release version, and I'm pretty good about keeping it patched.

    I'm bold enough to run some beta stuff (usually in a VM) but not in this case since this system is the heart and soul of all my testing environments, and therefore very mission critical to me.

    FYI whenever I refer to HVM, it's generally running on my Vista desktop..  The server is in a rack in the server room, I almost never touch it physically.. it's all managed from my Vista box for the most part, either via HVM, the wonderful Hyper-V Monitor sidebar tool (you can thank me that it displays free memory on the host, something not even HVM shows me) or if needed remote desktop.

    I also intereact with the VM's almost entirely via 'Console' sessions on my workstation.

    If you can hand me a server to run it, and 3 or 4 more hours in the day, I'd gladly play with the beta however..
    --Chuck
    Wednesday, March 25, 2009 10:58 PM
  • I am having this same problem.  I have several Hyper V machines and last night we had a major power outage here which shut down several of our systems.  This morning, the network connection in our Hyper V server appears to be corrupt and if I create a new one and link it to a virtual machine without snapshots, it works fine.  However, I cannot restore any of the snapshots on the machines because of errors with the network adapter.  There has to be a way to fix this even if its manually modifying the xml file.  I cannot toss all the snapshots I created and start over.  Please help.
    Thursday, May 21, 2009 12:38 PM