locked
Partioning Hyper-V vhds RRS feed

  • Question

  • I have a Hyper V server setup with a C drive (RAID1) for the OS and a D drive(RAID5) for my vhd files essentially splitting the OS from the Data files physicially.  My question is how should I setup the vhd systems?  My vhds at this point are a file server, voice mail server, and application server.  Do they need a C and D drives as well or should everything be housed in their respective vhd files?  I am trying to find that magic balance between performance and DR.

    I like having everything within the vhds due to diaster recovery aspect because all I have to do is copy the exported data over to another Hyper V server, turn it on, restore the data files if needed and I am done.  However I dont think this is the best approach especially for the application and file server.  My first thought was to create space on a NAS and connect a D drive to the NAS that way the data/application drives are not only on a seperate drive but on a seperate system, however I am worried about throughput issues.  

    Any help or suggestions will be appreciated.

    Thanks,
    Mitch
    Monday, March 2, 2009 1:12 AM

Answers

  • Hi Mitch,

    I personally have found that the biggest problems that you will run into with Virtualization are disk I/O issues.  That said I like to keep that side of the house as straight and narrow as possible.  Due to this I generally follow a few rules.  These are specific to non-HA VMs those require a different kind of thinking that I won't go into here.

    -System and Programs installed on VHD file stored on Host.  This is the Guest C: drive.
    -Assuming that this is something that uses a large amount of storage or a disk intensive service (database/logs) then these would be stored on separate iscsi SAN attached volumes.
    -Try and minimize the size of the VHD files.  Encapsulating stuff in the VHD results in a little bit of overhead.
    -Use iso images attached as CD drives instead of copying installers to the C$.

    That said as long as you offload as much i/o as possible then you should be good to go.  This gives you an added benefit from a DR perspective of being able to move the VM from host to host without moving that storage.  Also to migrate it to another VM or physical machine you can just detach and reattach the LUN.

    -matt


    If this post is helpful, please mark it as such.
    • Marked as answer by mitchodell Monday, March 2, 2009 3:18 PM
    Monday, March 2, 2009 5:09 AM

All replies

  • Hi Mitch,

    I personally have found that the biggest problems that you will run into with Virtualization are disk I/O issues.  That said I like to keep that side of the house as straight and narrow as possible.  Due to this I generally follow a few rules.  These are specific to non-HA VMs those require a different kind of thinking that I won't go into here.

    -System and Programs installed on VHD file stored on Host.  This is the Guest C: drive.
    -Assuming that this is something that uses a large amount of storage or a disk intensive service (database/logs) then these would be stored on separate iscsi SAN attached volumes.
    -Try and minimize the size of the VHD files.  Encapsulating stuff in the VHD results in a little bit of overhead.
    -Use iso images attached as CD drives instead of copying installers to the C$.

    That said as long as you offload as much i/o as possible then you should be good to go.  This gives you an added benefit from a DR perspective of being able to move the VM from host to host without moving that storage.  Also to migrate it to another VM or physical machine you can just detach and reattach the LUN.

    -matt


    If this post is helpful, please mark it as such.
    • Marked as answer by mitchodell Monday, March 2, 2009 3:18 PM
    Monday, March 2, 2009 5:09 AM
  • It sounds like I am going in the right direction.  The only problem is I dont have the money to invest in an iSCSI setup right now.  In the future it sounds like that is the way to go.  What I am thinking of doing at this point is splitting the OS and data on Virtual Servers across two vhd files (C&D).  They will still be housed on the D drive (RAID5) of the Host OS but once I do get the capital to invest in an iSCSI system it shouldnt be that hard to port the D drive vhd over to the external storage? The way I will battle disk IO until I get a better NAS/DAS in place will be to load balance between my two virtual servers that I currenlty have by putting the most active systems with the least active systems.

    -mitch 
    Monday, March 2, 2009 3:46 PM
  • I see this reply is rather late, I know this is an MS site but that said you can use FreeNAS which is fairly easy to setup which now supports iScsi. I have done this using an old box with a mirrored pair of 500g drives and it works great. Hyper V (and VMware) have no problems seeing it.
    Tuesday, January 18, 2011 2:20 AM