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Performance of Hyper-V

    Question

  • Dear all,

    We installed a standalone Windows Server 2016 with the Hyper-V role some months ago. The storage for the VM is a Synology NAS (connected through iSCSI). A virtual machine was created with Windows Server 2012 R2. An oracle Database is installed on it. To do this, we attached a second VHDX file of 2TB size (fixed disk). The creation of this second VHDX was slow (one night to create it).

    Now we try to clone this virtual machine (Export+Import it) on the same Hyper-V. The problem is that the import of the cloned VM is very slow. I think it is normal because 2TB are moved bits per bits... Other people pretended it can be caused by Synology performance, but I tested it by copying an ISO file (4GB) from Hyper-V to the iSCSI volume and it takes less than 30 seconds...

    By this test, I believe it is not related to latency between Hyper-V and NAS (there are directly connected each other, no switch between because this last caused a lot of latency before). By seeing the preceding test (see image above), Synology seems to provide good performance through iSCSI.

    So my question is: Is it normal that a 2TB vhdx file takes about 15 hours (maybe 1 day?) to be copied (through VM importation)? If no, is it related to a performance issue of the Hyper-V itself (assuming that NAS Synology provides good performance)? How to check it?

    Thank you in advance for your answers,

    Lucas

    Wednesday, February 22, 2017 9:32 AM

Answers

  • Hi Lucas,

    >>Is it normal that a 2TB vhdx file takes about 15 hours (maybe 1 day?)

    I suppose the process would take more time if the file is large.

    But I'm afraid there is no method to calculate the time it needs. The importing process also requires CPU processing and RAM usage, not only related to the transfer speed between storage.

    Your scenario seems to be taking too much time, not sure if it is normal considering performance issues are really difficult to reproduce to analyze.

    Best Regards,

    Leo


    Please remember to mark the replies as answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Thursday, February 23, 2017 2:37 AM
    Moderator

All replies

  • Hi Lucas,

    >>Is it normal that a 2TB vhdx file takes about 15 hours (maybe 1 day?)

    I suppose the process would take more time if the file is large.

    But I'm afraid there is no method to calculate the time it needs. The importing process also requires CPU processing and RAM usage, not only related to the transfer speed between storage.

    Your scenario seems to be taking too much time, not sure if it is normal considering performance issues are really difficult to reproduce to analyze.

    Best Regards,

    Leo


    Please remember to mark the replies as answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Thursday, February 23, 2017 2:37 AM
    Moderator
  • Hi,

    Are there any updates?

    You could mark the reply as answer if it is helpful. 

    Best Regards,

    Leo


    Please remember to mark the replies as answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Thursday, March 09, 2017 11:52 AM
    Moderator