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Windows Various ESXi questions including running an Active Directory Domain Controller

Discussion in 'Software' started by Chicken76, 7 Oct 2012.

  1. saspro

    saspro IT monkey

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    I have 12 physical & 12 hyperthreaded cores per blade & 196GB RAM per blade.

    All vm's have between 2-8 vcpu's per server.

    I have 95GHz total CPU resources available. I have 57GHz available
     
  2. Chicken76

    Chicken76 Active Member

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    Thanks guys. That's all very useful info for me.

    You mean the hardware has 95 GHz total resources, and you allocated 38 to VMs leaving 57 available?

    Edit: Does anyone have any experience with ESXi on AMD hardware?
     
  3. saspro

    saspro IT monkey

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    Correct.

    There's not much difference with AMD or Intel on ESXi (unless you try moving between platforms)
     
  4. Chicken76

    Chicken76 Active Member

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    As I understand, moving a VM between Intel and AMD hosts is possible, but not while the VM is running. So you can't do HA, but if you shut down the VM on one host, you can start it on the other. I'm assuming the guest OS will see the new type of CPU, install drivers, etc. and probably Windows will need a reboot. Am I mistaken?
     
  5. saspro

    saspro IT monkey

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    That's what it should do.
    Although you do need a good tidy up of the guest afterwards & have to re-apply IP's etc as it keeps them linked to the old missing hardware
     
  6. Chicken76

    Chicken76 Active Member

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    Why would the virtual NICs change when moving to a host with a different architecture?
     
  7. saspro

    saspro IT monkey

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    Because it does. No logic, it's a "feature" of Windows etc
     
  8. Zoon

    Zoon Hunting Wabbits since the 80s

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    For you to move a VM between hosts they need to be near enough identical, and licensed for HA - otherwise as saspro says you've gotta do it all manually.

    If you're talking about a disaster recovery scenario then a couple hours may be enough for you.

    Otherwise just buy two identical servers and the HA licensing required! :)
     
  9. Chicken76

    Chicken76 Active Member

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    But if you move (manually, no HA) a VM from one Intel server to a different generation Intel server, are there any mismatches at the guest level, any detection/installation phase?
     
  10. saspro

    saspro IT monkey

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    It's a world of pain.

    You can't go back generations without issues (as certain features won't exist etc), usually you find the VM won't start.

    If you're moving VM's you need the same hardware.
     
  11. Chicken76

    Chicken76 Active Member

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    But hardware dies, goes obsolete. Is at least moving forward easier?
     
  12. saspro

    saspro IT monkey

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    Moving forwards works, it's if you only upgrade one host in your cluster you have issues.
     
  13. Chicken76

    Chicken76 Active Member

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    But even if you move forwards there's still some detection/installation involved, right?
    And I suppose once that's done, moving back to the original hardware is not possible.
     
  14. saspro

    saspro IT monkey

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    It's essentially the same as taking your old HDD and sticking it in a new machine.
    Windows installs stuff and hopefully works.

    You can sometimes go back but depends on what you've moved from.
     
  15. Chicken76

    Chicken76 Active Member

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    But then, moving between identical machines would also mean some detection&installation, since the new hardware has other S/Ns and Windows will perceive it as different hardware.

    I would have thought there was more hardware virtualization, to allow for easier migration.
     
  16. saspro

    saspro IT monkey

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    Migrating between identical hardware is seamless, no redetection at all.
    There's no serial numbers etc in hardware to worry about.
     
  17. Zoon

    Zoon Hunting Wabbits since the 80s

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    You may be able to achieve what you're looking to do with VMware Convertor.

    Point it at an ESX/ESXi host and you can convert a virtual machine from one format to another.

    Simply convert it to the same format and point the destination at your other host.

    It'll take care of the changing hardware required in the other host.

    This is not seamless and comes with its own issues. You'd only use this for a permanent transfer from one host to another.

    I'd like to stress - again - that you really are best to just have an identical pair of hosts. You'd be surprised how much CPU and RAM you can get in a Dell R620 for £3000 a server and they use next to no power. With two low power quad-core CPUs and 64gb low power ram, we're looking at 137 watts for 35% load which is frankly mental.
     
  18. Chicken76

    Chicken76 Active Member

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    OK, last question regarding VM transfers (for now): Is the transition easier between hosts of the same generation but different manufacturers?
     
  19. saspro

    saspro IT monkey

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    No sure I never do it.

    I just buy 3 identical servers for each install
     
  20. Zoon

    Zoon Hunting Wabbits since the 80s

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    If you managed to get three vendors using the exact same motherboard, CPU, network adaptors and other devices, then that would more than likely be fine.

    The chances of that are small though.

    You might be better considering application-level redundancy instead of working out how to migrate your guests in a hurry i.e. have two of everything. You should always have at least two domain controllers anyway but other apps often support some kind of application-level HA.
     

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