Virtualization1

Discussion in 'Trading Software' started by pkts, Aug 5, 2009.

  1. Depends on your memory usage.

    There are SIGNIFICANT advantages of the 64 bit OS - even when running 32 bit software - once you start hitting the 3.6gb max limit of the 32 bit OS.

    I question, though, the smartness of running XP to start with. Especially with a proper virtualization host, you are better off runing Windows 7 / 2008 Server R2 (actually the last really more recommended) on a Hyper-V virtualization platform.

    No need to install any drivers ;) Among other things ;)
     
    #31     Sep 13, 2009
  2. I need to use XP Pro 32 or 64 bit; Vista, Windows 7 (any release) or server 2008 are out of question.

    The scenario would be to run 1/2Gb RAM guests running XP 32 bit under a 4/8Gb host machine running XP Pro x64.

    Anyone else?
     
    #32     Sep 13, 2009
  3. WHY?

    What is the technical reason?

    Note "no clue and dont get it working" is not a technical reason.

    You run an OS that ends soonish official support.

    WIth 1-2 gb is will make no difference, btw. I suggest staying with 32 bit then.
     
    #33     Sep 13, 2009
  4. Isn't a 32 bit virtual machine running at least partially 'cached' into host 64 bit memory?
     
    #34     Sep 14, 2009
  5. That does not help if the 64 bit host does not have a memory surplus to start with.

    Basically:

    max memory 32 bit: 4gb, in MOST cases 3.6gb usable.

    max memory 64 bit - a LOT more.

    But if you run a 2gb 32 bit machine on a 3gb 64 bit host - the host side caching can not materialize. Because there is no RAM to cache into. In that case it is better to run a 32 bit host with 3gb and no virtualization, as that eats some more memory.

    OTOH, if you put 2gb 32 bit machine on a 64 bigt host with 16gb RAM - the host has a TON of ram to do IO caching ;)

    Now, "value providers" trying to be as cheap as possible will do what?

    Exactly - they will load the host as high as they can. Plus possibly have cheap but large discs under them. THis means:
    * No caching really happens
    * The IO subsystem is a lot slower than on a real machine, because the slow discs one may buy for himself... now get split over 15 or 20 machines.
    * Oh, btw., hope people do not USE Their machines, as the CPU otherwise is - hm - equally divided. This means pretty crappy.

    A high performance host will:
    * Set aside a proper overhead factor for his virtual machines. Say, reserv 20% of so of the memory for caching.
    * Have a high end but expensive IO Subsystem, possibly using a SAN. I personally use Adaptec RAids at the moment with Battery unit, write back cache and the VM hosts run on a RAID 10. That is a LOT of money in discs for a mere 600gb volume.
    * Look at CPU and distribute that evenly.

    But then, this is not going to be a LOT cheaper than a dedicated server. It has a LOT of advantages (less power, better maintenance etc.), but it is not "get me a 2gb machine for 9.99 USD per month".

    The difference gets visible, or example, when you have to reset the host (because yes, there are patches there, too) and then hit "start" on 20 vm's at the same time ;) MINE just come up - the IO just gets eaten. The cheap setup I used before (and we still use sometimes for really low end machines, or developer systems) takes minutes to start... because the discs just crap out with IO.
     
    #35     Sep 14, 2009
  6. Ok, finally it's clear; the host is a 8 Gb machine running on 10K rpm HD. thanks :D
     
    #36     Sep 14, 2009
  7. Ah, that does not sound too bad then ;) Have fun ;) I do have - virtualization is terrific if properly used. This CAN include high performance machines (like a db server) - not to save money, but for a lot of other advantages. Just dont abuse it ;)
     
    #37     Sep 14, 2009