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Multiple VHD files per VM and RAID 10 Allocation RRS feed

  • Question

  • This is new territory for me so if the question is stupid forgive me.  I am reading a book on Hyper-V 2012 and I have come across something I don't understand.  The book states that a VM can have multiple VHD's stored on a single LUN (in this case a RAID 10) but only one VHD file can take advantage of the benefits of the RAID 10.  All other files are regulated to RAW disk and can't take advantage of the striping and mirroring of RAID 10.  Is this so and why?  Thanks for your help.


    Michael T. Glenn

    Saturday, August 3, 2013 5:06 PM

Answers

  • Hi Michael,

    Partly because in storage level there is LUN & Raid.

    Both are different components that we are looking at today.

    furthermore Raid can be configure via Raid 1 to 10 depending on how many disk were provision.

    Why multiple VM cannot utilize RAID 10 performance ?

    Ans: http://serverfault.com/questions/223031/raid-10-or-raid-5-for-multiple-vms-what-is-the-best-choice

    Raid functionality

    raid 1 = 2 hard disk

    raid 5 = minimum 3 disk, but recommended 4 disk because logical 0 & 1 will be use for mirroring and 2 & 3 for IO read / write

    raid 10 = minimum 5 disk for optimum performance.


    Guowen Su
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    • Proposed as answer by Soh.M Sunday, August 4, 2013 1:46 PM
    • Marked as answer by Soh.M Thursday, October 3, 2013 6:00 AM
    Sunday, August 4, 2013 1:46 PM
  • raid 10 = minimum 5 disk for optimum performance.

    I believe RAID10 requires an even number of spindles. Inasmuch as it is a mirror of striped disks, the total quantity of disks will be two times (the number of disks in the stripe set), which makes it always an even number. The minmum number of disks required for RAID10 is four. The optimal number of disks is "as many as you can get".

    Nothing in the cited article talks about this non-sequiter of "only one VHD can take advantage of the benefits of RAID10". The FILES stored on a RAID array are irrelevant to the RAID technology implemented on that array. The benefits of the array accrue to all files stored on the array, whether they're JPEGs, AVIs, or VHDs.

    Furthermore, I'm not seeing anything in your response that answers that question either -- and I was most intrigued to see what sort of rationalization would come up to draw such a conclusion.

    @Michael - what is the title of this book and what page did you find this reference? I'd like to take a look at it myself and see it in context.


    Lawrence Garvin, M.S., MCITP:EA, MCDBA, MCSA
    SolarWinds Head Geek
    Microsoft MVP - Software Packaging, Deployment & Servicing (2005-2013)
    My MVP Profile: http://mvp.support.microsoft.com/profile/Lawrence.Garvin
    http://www.solarwinds.com/gotmicrosoft
    The views expressed on this post are mine and do not necessarily reflect the views of SolarWinds.

    • Marked as answer by Soh.M Thursday, October 3, 2013 6:00 AM
    Tuesday, August 6, 2013 7:43 PM

All replies

  • Hi Michael,

    Partly because in storage level there is LUN & Raid.

    Both are different components that we are looking at today.

    furthermore Raid can be configure via Raid 1 to 10 depending on how many disk were provision.

    Why multiple VM cannot utilize RAID 10 performance ?

    Ans: http://serverfault.com/questions/223031/raid-10-or-raid-5-for-multiple-vms-what-is-the-best-choice

    Raid functionality

    raid 1 = 2 hard disk

    raid 5 = minimum 3 disk, but recommended 4 disk because logical 0 & 1 will be use for mirroring and 2 & 3 for IO read / write

    raid 10 = minimum 5 disk for optimum performance.


    Guowen Su
    Cisco Certified Network Associate
    Cisco Certified Internetwork professional - MPLS
    Certified Information Systems Security Professional
    Microsoft Partner Network 2011
    Microsoft Certified Professional
    Microsoft Certified Systems Administrator:Security
    Microsoft Certified Systems Engineer: Security
    Microsoft Certified Technology Specialist: Windows Server 2008 Active Directory, Configuration
    Microsoft Certified Technology Specialist: Windows Server 2008 Network Infrastructure, Configuration
    Microsoft Certified Technology Specialist: Windows Server 2008 Applications Infrastructure, Configuration
    Microsoft Certified Technology Specialist: Windows 7, Configuring
    Microsoft Certified IT Professional: Enterprise Administrator
    Microsoft Certified IT Professional: Server Administrator
    Certified Ethical Hacker
    Computer Hacking Forensics Investigator
    Certified Sonicwall Security Administrator
    Microsoft Geeks

    • Proposed as answer by Soh.M Sunday, August 4, 2013 1:46 PM
    • Marked as answer by Soh.M Thursday, October 3, 2013 6:00 AM
    Sunday, August 4, 2013 1:46 PM
  • raid 10 = minimum 5 disk for optimum performance.

    I believe RAID10 requires an even number of spindles. Inasmuch as it is a mirror of striped disks, the total quantity of disks will be two times (the number of disks in the stripe set), which makes it always an even number. The minmum number of disks required for RAID10 is four. The optimal number of disks is "as many as you can get".

    Nothing in the cited article talks about this non-sequiter of "only one VHD can take advantage of the benefits of RAID10". The FILES stored on a RAID array are irrelevant to the RAID technology implemented on that array. The benefits of the array accrue to all files stored on the array, whether they're JPEGs, AVIs, or VHDs.

    Furthermore, I'm not seeing anything in your response that answers that question either -- and I was most intrigued to see what sort of rationalization would come up to draw such a conclusion.

    @Michael - what is the title of this book and what page did you find this reference? I'd like to take a look at it myself and see it in context.


    Lawrence Garvin, M.S., MCITP:EA, MCDBA, MCSA
    SolarWinds Head Geek
    Microsoft MVP - Software Packaging, Deployment & Servicing (2005-2013)
    My MVP Profile: http://mvp.support.microsoft.com/profile/Lawrence.Garvin
    http://www.solarwinds.com/gotmicrosoft
    The views expressed on this post are mine and do not necessarily reflect the views of SolarWinds.

    • Marked as answer by Soh.M Thursday, October 3, 2013 6:00 AM
    Tuesday, August 6, 2013 7:43 PM