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Converting Dynamic disk to Fixed

    Question

  • Hi guys,

    I was hoping someone would be able to help me with this.

    I have created 300GB disk called vAPP on SAN.

    Added the disk as cluster shared volume in Failover cluster manager (Server 2012 R2) and currently running VM on this disk.

    Just realized that it is Dynamically expanding virtual hard disk and need to convert it to Fixed.

    In order to convert the disk i need another 300GB if i understand instructions correctly.

    Does Microsoft mean that i need 300GB on a Host or do i need to expand existing vAPP disk in SAN?

    Many thanks

    Milan

    Monday, April 10, 2017 10:12 AM

All replies

  • First thing to think through is whether or not you really need to convert dynamic to fixed.  The performance difference between the two is slight, and once the dynamic disk expands to its maximum, you will no longer see any performance difference at all.  Given the slight performance difference (in many applications the difference is not even noticeable), what do you gain by converting?

    When it comes to converting from one format to another, you need enough space on the destination location to contain a brand new VHD of the size you want to create.  You do not increase the size of the existing VHD because you are creating a new VHD from the existing VHD.


    tim

    Monday, April 10, 2017 1:22 PM
  • Hi Tim,

    We are having some performance issues and Microsoft wouldn't go any further until we convert do fixed. 

    When you say destination, do you mean the SAN? 

    I have created another 300GB disk in SAN and added the disk to cluster through storage-disks.

    While converting the first disk do I point it to newly created disk?

    Milan

    Monday, April 10, 2017 1:45 PM
  • "While converting the first disk do I point it to newly created disk?"

    If you plan on performing the copy of the data from the dynamic to the fixed yourself (which is one way to do it), then you would create your own fixed disk and assign it to the VM.

    If you are going to use the Edit disk/Convert option of Hyper-V, Hyper-V will create its own destination disk.


    tim

    Monday, April 10, 2017 1:57 PM
  • sorry for asking silly questions but how would i do this? 

    "If you plan on performing the copy of the data from the dynamic to the fixed yourself (which is one way to do it), then you would create your own fixed disk and assign it to the VM."

    I am very new to Hyper-v so not sure on how to. Do I go to Roles and add new disk and point to vFile01fixed disk.

    How would i move the whole VM with all the settings on to a new disk.

    Monday, April 10, 2017 2:29 PM
  • I thought i will follow this link http://www.hyper-v-mart.com/Howto/Convert_Hyper-V_Dynamic_Disk_to_Fixed_Disk.aspx

    but when it comes to step 6 then i am not sure on how to point it to SAN there. I wouldn't have enough space available on host as there is only 200GB 

    • Proposed as answer by VR38DETTMVP Sunday, April 23, 2017 6:21 PM
    Monday, April 10, 2017 2:57 PM
  • Hi Sir,

    >>I have created another 300GB disk in SAN and added the disk to cluster through storage-disks.

    >>We are having some performance issues and Microsoft wouldn't go any further until we convert do fixed. 

    It is a hyper-v cluster , right ?

    The VM which facing performance issue was stored in CSV , right ?

    If you are going to convert the dynamic VHD to  fixed , you can check the size demand of VHD file converting (max size - current file size ) , it shouldn't be larger than the CSV free space which holding that VHD file .

    >>but when it comes to step 6 then i am not sure on how to point it to SAN there

    Please navigate to "C:\ClusterStorage" to find the CSV disk name .

     

    Best Regards,

    Elton


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    Tuesday, April 11, 2017 1:30 AM
    Moderator
  • Hi Elton,

    yes it is Hyper-V and the VM is in CSV. 

    Thank you for your help, just got confused on where the file is created. 

    Will give it a go and let you know.

    Many thanks

    Milan

    Tuesday, April 11, 2017 8:50 AM
  • Hi Sir,

    How are things going ?

    Best Regards,

    Elton


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

    Sunday, April 23, 2017 9:19 AM
    Moderator