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Advise on memory allocation for a vm

    Question

  • Dear all,

    I have a host server with 4 GB of RAM.

    I need to setup 2 VM's, what should be the good VM memory choice ?

    regards

    serge


    Your knowledge is enhanced by that of others.
    Tuesday, August 23, 2011 4:18 PM

Answers

  • Sharepoint 2010 has a min RAM req of 4GB/8GB dev/production use.  I don't recall if it prevents you from installing when you have less than 4GB.

    Will the server OSes in the VMs be 2003 or 2008?  WSUS on 2003 is fairly small.  Dynamics CRM wants 1GB.

     

    Basically, there is nothing magical about virtual machines.  If you need a minimum of 2GB to run the server on physical hardware, you're going to need the same minimum amount of RAM in a VM.  Of course, if you're working with dynamic memory you can get away with less total RAM on a server when you're consolidating to VMs.

    Tuesday, August 23, 2011 8:50 PM

All replies

  • No one can tell you this without more information.

    What OS, applications, work-load, etc for the VMs? 

    What is the host OS: Hyper-V server, Server Core with Hyper-V, full Windows Server with Hyper-V?

     

    Tuesday, August 23, 2011 4:56 PM
  • Sorry,

    host server is running Server 2008 Enterprise R2

    Aplication that will run on VM 1 : WSUS and CRM

    Application that will run on VM 2 : Team Foundation Server, Sharepoint Service


    Your knowledge is enhanced by that of others.
    Tuesday, August 23, 2011 5:07 PM
  • I am guessing that if you check the recommendations of the products you listed that you do not have enough RAM to support these two VMs.  That does not meant that it will not work.

    WSUS is realatively low overhead.  It all depends on the number of clients.

    "CRM" is a big thing.  Some have high overhead, others not so much.

    TFS is a resource hog as well as Sharepoint.  enough said.

    If this is a production deployment, you don't have enough RAM.  If this is simply a little test environment start by giving each VM 1.5Gb of RAM.  Reserving 1Gb for the hypervisor.

    Turn on Dynamic Memory and watch your VMs while you do things.  It will give you a decent amount of feedback as to what is required and how the demand changes as what you and your VM does changes.

    That all being said there are many applications that can run low demand in 512 MB of RAM.  But then that I assuming that RAM is where your VM will starve first, not Disk I/O and not becuase it is a single threaded application which will cause CPU to starve instead.

     

     


    Brian Ehlert (hopefully you have found this useful) http://ITProctology.blogspot.com
    Tuesday, August 23, 2011 5:55 PM
  • Sharepoint 2010 has a min RAM req of 4GB/8GB dev/production use.  I don't recall if it prevents you from installing when you have less than 4GB.

    Will the server OSes in the VMs be 2003 or 2008?  WSUS on 2003 is fairly small.  Dynamics CRM wants 1GB.

     

    Basically, there is nothing magical about virtual machines.  If you need a minimum of 2GB to run the server on physical hardware, you're going to need the same minimum amount of RAM in a VM.  Of course, if you're working with dynamic memory you can get away with less total RAM on a server when you're consolidating to VMs.

    Tuesday, August 23, 2011 8:50 PM
  • Hi,

     

    As the above guys mentioned, you can assign memory to the VMs optionally. However, the actual requirements will depends on the application running with the VMs.

     

    By the way, I have experience with a Hyper-V computer with 2GB’s memory, when I tried to start a VM with 1GB’s memory, it failed as there wasn’t enough memory. So you may encounter the same issue if you want to leave 1GB’s memory for Hyper-V host machine.

     

    In addition, ram is very cheap now, why not add some memory to the computer? That will improve the performance of both Hyper-V host machine and the VMs running on it.

     

     

    Best Regards,

    Vincent Hu

     

    Wednesday, August 24, 2011 2:44 AM
  • i will do
    Your knowledge is enhanced by that of others.
    Wednesday, August 24, 2011 3:58 AM