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Best Hyper-V Server physical drive arrangement

Answered Best Hyper-V Server physical drive arrangement

  • Tuesday, December 30, 2008 5:22 PM
     
     
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    Can someone here give me some guidance as per the physical drive arrangement on my new PowerEdge 2900 III server for Hyper-V.

    Current Configuration :
          2 - 146 GB 15k SAS drives in RAID 1 configuration for the Hyper-V OS
          1 - 300 GB 15k SAS drive in RAID 0 configuration for the Hyper-V virtual machines and virtual drives 

    Proposed Storage Additions:
          Method 1:
          Add 2 - 300 GB 15k SAS drives ( to expand the original RAID 0 configuration to 900GB)
          1 - 1 TB 7200k SAS drive ( for a new RAID 0 configuration to be used for backup of the Hyper-V virtual machines and virtual drives )
          
          Method 2:
          Add 2 - 300 GB 15k SAS drives ( each drive being a new RAID 0 configuration and stand alone drive)
          1 - 1 TB 7200k SAS drive ( for a new RAID 0 configuration to be used for backup of the Hyper-V virtual machines and virtual drives )

    Which drive configuration would Hyper-V be more happy with?  Mehod 1 ( one D:\ drive -- three physical drives as a RAID 0 of 900GB )
    or Method 2 ( three D:\. E:\ and F:\ drives of 300 GB each.)

    Then either method will use the Windows Server Backup Utility or a PowerShell script kicked off with Task Scheduler to backup the Virtual Machines  to the 1 TB near-line SAS drive on a regular basis for recovery purposes.

    Orgbrat

     

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  • Tuesday, December 30, 2008 6:07 PM
     
     
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    Since disk is the most common limiting factor in virtualization environments, I would recommend using method 1.

    By adding the 300GB drives to the current RAID0 container you will be able to use the benefits of a volume, striped over multiple disks (faster read speeds, compared to three stand-alone disks) and less overhead (the storage controller will only need to manage 1 container, instead of 3)
     
  • Tuesday, December 30, 2008 7:05 PM
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    As a general rule, maximizing disk speed is prudent and RAID 0 stripes help with that.

    You didn't mention how many virtual machines will be running simultaneously and what the usage patterns are. Sometimes disk contention is a more significant issue than raw speed. If disk contention causes waits, then independence of disks may be more valuable.
     
  • Wednesday, December 31, 2008 12:39 AM
     
     
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    Hi folks,
           Thanks for the quick replies. The server is being set up as a Hyper-V virtualized development and test environment. I am a software developer and need to test many different combinations for my software. So really the usage is low and controlled with maybe 1 to 5 virtual machines running at any one time. But I need the space so that I may have all these different virtual machines setup allowing me to take advantage of whatever technology that I might need during that testing.

    I already have 7 virtual machines and two thirds of my original 300GB is gone. So disk space is the current limiting factor. I am trying to determine what the best way would be for me to get most disk space and still be able to recover from a disk failure. It has been recommended that I might try RAID 5 for the virtual machines drive. This would be an optional choice, but I would loose 300GB of space down to 600GB. But that would allow the third 300GB to handle a single drive failure if it occurred. But makes me question the 1 TB near-line drive I bought for backup. With the 15k 300GB drives being $650.00 each and the 1 TB 7200k near-line drive being $240.00, I thought using all 15k 300GB drives for disk space was possibly the best answer.

    I am concerned about drive failure as creating all these different virtual machines is time consuming. I guess I am just trying to figure out how to get the best of both worlds disc storage space and some kind of recovery option ( backup plan ).

    I hope the hardware is covered with the DELL PowerEdge 2900 III:
        Dual Quad Core 2.66 Xeon Processors
        32GB Memory
        PERC 6/I SAS Integrated Controller.


    Orgbrat

     
  • Wednesday, December 31, 2008 9:26 AM
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    Hi,

     

    According to your description, you want to get the best of both worlds disk storage space and some kind of recovery option.

     

    Generally speaking, if you want to have a best disk failure recover, it will cost you the most disk space for the backup. The utilization ratio of the disk space is inversely proportional to the disk failure recover.

     

    Analysis:

     

    1. Raid-0

     

    In Raid-0, you will get the maximum disk speed and the whole disk space. However, there is no redundancy. Failure of any drive results in loss of all data.

     

    2. Raid-5

     

    In Raid-5, disk space = (Size of Disk Drive) * (Number of Drives - 1). The disk speed here is a bit lower than Raid 0, failure of any drive can't results in loss of all data.

     

     

    In this case, there may be two methods for you based on your current state:

     

    Method 1, Raid-5:

     

    Use 3 pieces 300 GB 15k SAS drives (or more) to set Raid 5.

     

    Method 2, Raid-0 + Backup:

     

    Use 3 pieces 300 GB 15k SAS drives (or more) to set Raid 0, and at the same time use Windows Server Backup Utility and Task Scheduler to backup the Virtual Machines  to the other 1 TB SAS drive.

     

    In addition, here are some suggestion, just for your reference:

     

    1.   Store OS and Data in different disks.

    2.   Use Pass-Through disk in Hyper-V to provide the better performance for performance critical applications.

     

    To design an appropriate disk configuration, I would like to suggest that you first analyze and prioritize your requirements and then refer to the following links and whitepapers on Hyper-V performance tuning guidance.

     

    Storage options for Windows Server 2008 Hyper-V

    http://blogs.technet.com/josebda/archive/2008/02/14/storage-options-for-windows-server-2008-s-hyper-v.aspx


    Performance Tuning Guidelines for Windows Server 2008

    http://www.microsoft.com/whdc/system/sysperf/Perf_tun_srv.mspx

     

    Best regards,

    Vincent Hu

     
  • Wednesday, December 31, 2008 8:05 PM
     
     
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    Well, I will have to say that you guys have almost convinced me to buy two more ST3300656SS ( SAS Seagate Cheetah® 15K.6 ) 300GB hard drives and configure a RAID 5 array with 4 300GB drives and an additional Hot Spare. That would get me the fail-over drive within the RAID 5 configuration and a spare Hot swap drive, just in case. And I would still have the 900GB of drive space.  And the backup ST31000640SS ( SAS Barracuda ES2 ) 1TB drive would almost back up both the C:\ (OS Drive ) and the D:\ ( Data Drive ) assuming they were both not completely full.



    Right now, my only concern would be the performace of the virtual machines within Hyper-V using the RAID 5 configuration.



    I need to do some thinking about this, but I see two more drives and caddies coming.



    Orgbrat

     
  • Thursday, January 01, 2009 4:21 PM
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    Tony has some analysis here - http://blogs.msdn.com/tvoellm/archive/2008/09/24/what-hyper-v-storage-is-best-for-you-show-me-the-numbers.aspx for RAID 0 configs.
    Chuck Timon Senior Escalation Engineer (SEE) Microsoft corporation
     
  • Thursday, January 01, 2009 6:41 PM
     
     
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            Thanks for the link to Tony's article. It was very interesting, although now I am really back up on the decision fence. After reading the article, I almost believe that I was going down the right path in the first place. 3-300GB 15k SAS drives in a RAID 0 configuration for the virtual drives and machines with a 1 TB 7200k SAS drive for backup and recovery. The backups being performed on a scheduled daily basis. Since this is a test and development Hyper-V server and usage is low and very controlled, this configuration would probably be satisfactory. Correct?


    Steve Graddy   MCP,  MCPS,  MCNPS,  MCAD
    Orgbrat Consulting ( Microsoft Certified Partner )

     
  • Thursday, January 01, 2009 7:05 PM
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    My Hyper-V server is for test and development. It has 6 15k SCSI drives in a RAID-0 for the vhds and 2 15k SCSI drives in RAID-1 for the OS. Hard drive I/O speeds on the RAID-0 array are outstanding. All drives are 160 GB.

    Although the entire RAID-0 array can't be backed up to the free space on the smaller RAID-1 array, the RAID-1 array is fully adequate for backup purposes. There are only a relatively few master "golden" vhds from which most of the other vhds are derived. Only the master vhds really need to be backed up - the rest can easily be recreated. Additionally, the derived vhds have short lifetimes in the testing process. They will probably be deleted before a disk failure occurs. The master vhds are kept in an NTFS compressed folder on the RAID-1 array. They take only about 60% as much disk space when compressed. The point is that in test and development environments, backup needs may not really be so demanding or extensive once you really analyze things.

    Your proposed configuration sounds satisfactory to me.

    Another great link on vhd performance can be found here: http://download.microsoft.com/download/d/9/4/d948f981-926e-40fa-a026-5bfcf076d9b9/SQL2008inHyperV2008.docx Although the title suggests it is specific to SQL Server, it has a lot of useful, generic content.
     
  • Thursday, January 01, 2009 8:41 PM
     
     
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    Again I have come full circle and back to where I started.  I guess my original feelings was more on target than what I had thought.
    This is a pretty low to mid range configuration, and will be the very lowest cost for the disk performance attained.

    Chosen Final Configuration:
          2 - 146 GB 15k SAS drives in RAID 1 configuration for the Hyper-V OS
          3 - 300 GB 15k SAS drive in RAID 0 configuration for the Hyper-V virtual machines and virtual drives  ( 900GB total )
          1 - 1 TB 7200k SAS drive ( for a new RAID 0 configuration to be used for backup of the Hyper-V virtual machines and virtual drives )

    After reading Tony Voellm's analysis here - http://blogs.msdn.com/tvoellm/archive/2008/09/24/what-hyper-v-storage-is-best-for-you-show-me-the-numbers.aspx for RAID 0 configs and all the other good articles linked in all of the other posts of this thread, I have came to the same conclusion as John Paul Cook  in this thread. It helped to see that someone actually had the same thoughts as I did. Now that does not make everyone else wrong, it shows that at least two people think the same way.

    Thanks....
     
    Steve Graddy   MCP,  MCPS,  MCNPS,  MCAD
    Orgbrat Consulting ( Microsoft Certified Partner )