locked
Can I place a VM on a GPT disk? RRS feed

  • Question

  • I want to place a virtual server on a GPT disk. The Hyper-V host server is running Windows 2008R2 SP1.

    The server is attached to a SAN Storage. I've created a 3TB volume on the SAN and mapped it to the host server.

    What I want to do is define this 3TB disk as a GPT disk and use it to store a virtual server. I plan to create two VHDs but both will be placed on the same physical volume.

    I plan to limit the size of the first VHD  to 100GB , this is where the Virtual server will boot from. It will be attached as IDE to the virtual server. Then I plan to add another VHD which I will limit to 2.9TB and attach to the Virtual Server as SCSI.

    Will this work? I mean will the VM have any problem booting from the 100GB VHD just because it is defined as GPT on the host?



    • Edited by Hard Stone Friday, September 7, 2012 3:35 PM
    Friday, September 7, 2012 3:34 PM

Answers

  • Hi!

    Using GPT is actually recommended in Server 2008 R2, and in most cases a necessity for drives larger than 2 TB.

    However, you can not create a vhd file larger than 2TB in Hyper-V 2008 R2, if you want the vhd to be 2.9TB, you need to use the new vhdx format available in Hyper-V 2012.

    You can create a disk greater than 2TB and assign to the VM using the pass-through option, but this means that the entire partition will be offline at host level, so it can't be shared with the 100GB vhd file.

    • Proposed as answer by Jeff Ren Monday, September 10, 2012 2:59 AM
    • Marked as answer by Jeff Ren Wednesday, September 12, 2012 6:03 AM
    Friday, September 7, 2012 3:40 PM

All replies

  • Hi!

    Using GPT is actually recommended in Server 2008 R2, and in most cases a necessity for drives larger than 2 TB.

    However, you can not create a vhd file larger than 2TB in Hyper-V 2008 R2, if you want the vhd to be 2.9TB, you need to use the new vhdx format available in Hyper-V 2012.

    You can create a disk greater than 2TB and assign to the VM using the pass-through option, but this means that the entire partition will be offline at host level, so it can't be shared with the 100GB vhd file.

    • Proposed as answer by Jeff Ren Monday, September 10, 2012 2:59 AM
    • Marked as answer by Jeff Ren Wednesday, September 12, 2012 6:03 AM
    Friday, September 7, 2012 3:40 PM
  • I have read your excellent  posts elsewhere and am hopeful you'll provide some advice. I am sure this info is "out there" but I don't quite know what the right questions are in order to find good answers.

    I have about 6TB (12 TB  currently built as a raid 10) I wish to use for a VM host running hyper-v and several VMs. What approach would you suggest taking for divvying up the storage on this machine? I plan to use fixed disk size among 6-8 VMs. 

    Some of the VMs will run Server 2003 and others, 2008. And I'd like to run one Linux VM. Is all this going to be possible or will I need to start by redoing my array? So many considerations...

    Thanks in advance for your insight.

    Thursday, September 13, 2012 7:06 PM
  • I have read your excellent  posts elsewhere and am hopeful you'll provide some advice. I am sure this info is "out there" but I don't quite know what the right questions are in order to find good answers.

    I have about 6TB (12 TB  currently built as a raid 10) I wish to use for a VM host running hyper-v and several VMs. What approach would you suggest taking for divvying up the storage on this machine? I plan to use fixed disk size among 6-8 VMs. 

    Some of the VMs will run Server 2003 and others, 2008. And I'd like to run one Linux VM. Is all this going to be possible or will I need to start by redoing my array? So many considerations...

    Thanks in advance for your insight.

    Hi!

    We have a lot of users posting here, that are working solely with storage in virtualization aspects as part of their day job. They will probably deliver a more accurate answer, but I'll give it a try.

    As with anything else when planning for virtualization, it depends on what you are virtualizing. For example, virtual terminal servers that will handle a large amount of logons will increase an considerable amount of disk activity, just as SQL servers with heavy workloads were recommended to store data on exclusive pass-through disks.

    I think that with 6-8 VMs (without knowing their roles) raid 10 is the most optimal raid level for you. Wheighing facts: While a VM will perform better with exclusive access to the physical storage,  a striped disk set performs better with every disk added to the array. Also dividing your disk pool into smaller arrays, could eventually turn out to become an administrative problem if a VM needs to be expanded in the future (I know that 6TB gets you far with VM's, but you might also want to create additional VM's.)

    So, with Raid 1 for host OS and Raid 10 for VM storage, I'd say you're good to go. (Assuming that you're using decent 10-15k disks at least and that your VM's will be average servers.)

    IMO, there is no globally correct answer, the best solution varies from case to case, and sometimes very hard to even make a plan for at all. The cool thing with virtualization (and especially with WS2012) is that you can move around your VMs to other servers while you reconfigure hosts for better performance.

    • Edited by Mike_Andrews Thursday, September 13, 2012 9:29 PM
    Thursday, September 13, 2012 9:21 PM