what is formula or logic of purchasing HYPERV
what is formula or logic of purchasing HYPERV or VMware for instance if I buy HP G8 server 2 processor and 120 GB RAM so how many VM's I can allocate what is the formula?
August 24th, 2015 12:43pm

Hello,

following is the licensing model with Windows Server 2012 R2 Editions:

  • Datacenter includes virtualization rights* for unlimited number of Windows Server VMs
  • Standard includes virtualization rights for 2 Windows Server VMs
  • Hyper-V Server does not include virtualization rights

* Example about virtualization rights: In case you purchase a Windows Server 2012 R2 Standard license for your physical server, you are allowed to run 2 Windows Server VMs on this server without purchasing extra licenses.

Except the licenses, it depends on your hardware how many VMs you will be able to run.
Typical bottlenecks are here the disks and memory. Make sure that you purchase at least 10K disks and run them in a RAID1.

Please note that for information regarding Microsoft Licensing, you should contact the Microsoft Licensing Team. Here in the forum we can't give definitive answers, only advices.

Best Regards,
Jens

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August 24th, 2015 1:03pm

With that information, no one can tell you.  You don't mention storage, which usually the first bottleneck, technically storage I/O.   How many cores do the CPUs have, that's also important.

What are your VMs doing?  CPU intensive, RAM intensive, disk intensive?  You need to get a good measure of your current environment.  If your VMs need 16-32GB of RAM vs 2-4GB of RAM that makes a huge difference in the number of VMs you're running.

There's no formula that works for all scenarios as everyone needs different things.

You can look at these tools to help you: http://h71019.www7.hp.com/ActiveAnswers/us/en/sizers/hp-sizer-server-virtualization.html

http://h20195.www2.hp.com/v2/GetPDF.aspx/4AA1-2975ENW.pdf

You still need to know the metrics of your environment.

August 24th, 2015 6:15pm

With that information, no one can tell you.  You don't mention storage, which usually the first bottleneck, technically storage I/O.   How many cores do the CPUs have, that's also important.

What are your VMs doing?  CPU intensive, RAM intensive, disk intensive?  You need to get a good measure of your current environment.  If your VMs need 16-32GB of RAM vs 2-4GB of RAM that makes a huge difference in the number of VMs you're running.

There's no formula that works for all scenarios as everyone needs different things.

You can look at these tools to help you: http://h71019.www7.hp.com/ActiveAnswers/us/en/sizers/hp-sizer-server-virtualization.html

http://h20195.www2.hp.com/v2/GetPDF.aspx/4AA1-2975ENW.pdf

You still need to know the metrics of your environment.

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August 24th, 2015 10:13pm

With that information, no one can tell you.  You don't mention storage, which usually the first bottleneck, technically storage I/O.   How many cores do the CPUs have, that's also important.

What are your VMs doing?  CPU intensive, RAM intensive, disk intensive?  You need to get a good measure of your current environment.  If your VMs need 16-32GB of RAM vs 2-4GB of RAM that makes a huge difference in the number of VMs you're running.

There's no formula that works for all scenarios as everyone needs different things.

You can look at these tools to help you: http://h71019.www7.hp.com/ActiveAnswers/us/en/sizers/hp-sizer-server-virtualization.html

http://h20195.www2.hp.com/v2/GetPDF.aspx/4AA1-2975ENW.pdf

You still need to know the metrics of your environment.

August 24th, 2015 10:13pm

With that information, no one can tell you.  You don't mention storage, which usually the first bottleneck, technically storage I/O.   How many cores do the CPUs have, that's also important.

What are your VMs doing?  CPU intensive, RAM intensive, disk intensive?  You need to get a good measure of your current environment.  If your VMs need 16-32GB of RAM vs 2-4GB of RAM that makes a huge difference in the number of VMs you're running.

There's no formula that works for all scenarios as everyone needs different things.

You can look at these tools to help you: http://h71019.www7.hp.com/ActiveAnswers/us/en/sizers/hp-sizer-server-virtualization.html

http://h20195.www2.hp.com/v2/GetPDF.aspx/4AA1-2975ENW.pdf

You still need to know the metrics of your environment.

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August 24th, 2015 10:13pm

Thanks kindly let me know how many maximum  number of VM can be installed on per host e.g 2 processor , 120 GB RAM, storage SAN around 20 TB again how to decide either host is capable to handle additional VM's or not I mean need to see any report? 
August 24th, 2015 10:31pm

https://www.virten.net/vmware/vmware-vsphere-esx-and-vcenter-configuration-maximums/ it shows maximum

VM supports per host and limitation it is right?

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August 26th, 2015 2:20am

"maximum  number of VM can be installed on per host e.g 2 processor , 120 GB RAM, storage SAN around 20 TB "

The number of VMs you can INSTALL is limited to the amount of storage on your system.  If you create one VM that uses 20 TB of storage, you can install a single VM.  If each of your VMs use only 2 GB of storage, then you can install about 10,000 VMs.  How many you can LOAD INTO MEMORY is limited to the amount of memory on your system.  Assume the hypervisor itself uses about 2 GB.  That leaves 118 GB (theoretically) available for VMs.  If you create one VM that uses 64 GB of memory and another that uses 54 GB, you can load two VMs.  If each of your VMs only takes 512KB of memory, you could load 236.  (Actually, it will be less because each VM needs some additional memory space in the hypervisor).  How many VMs can actually run is limited by the horsepower of the host system and the CPU requirements of the VMs.  There is no simple formula for this because it is completely dependent upon what the VMs are doing.  If they are simply sitting there with each one running its own operating system and no applications, you can get a lot of VMs 'running'.  However, if you have CPU-hungry VMs, you might get only a couple running.

What I am attempting to say here is that a lot more information needs to be provided in order to answer your question.  And you are the only one who will be able to answer it after you have gathered the disk, memory, and CPU requirements of the VMs you want to run.

August 26th, 2015 11:08am

1024 is the maximum number of VMs a host can run.  Which is largely irrelevant in the real world.

https://technet.microsoft.com/en-us/library/jj680093.aspx

I've given you sizing guides, you need to measure your environment to get a useful answer, fill in that info, and get a basic answer.

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August 26th, 2015 12:04pm

thanks my simple question if I am having 120 GB and created 6 VM's and allocated 20 GB each (6*20) 120 GB so can I create another VM's allocate again 20 GB? that is my question?
August 26th, 2015 10:50pm

Hi Cabpeter,

Since you have allocated all 120GB, we could not create a new VM unless we add more memory.

If you allocate 17GB to the 6 VMs, then we would be able to allocate 18GB to a new VM.

Here are the system requirements of Server 2008 and 2012, we could allocate memories according to them:
Windows Server 2008 System Requirements:
https://technet.microsoft.com/en-us/windowsserver/bb414778.aspx?f=255&MSPPError=-2147217396

System Requirements and Installation Information for Windows Server 2012 R2:
https://technet.microsoft.com/en-us/library/dn303418.aspx?f=255&MSPPError=-2147217396

Best Regards,

Leo

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August 27th, 2015 1:42am

thanks so total physical server RAM needs to use same amount of RAM meaning 120 GB physical RAM needs to allocate  only less than 120 GB not more than 120 GB my assumption is if I have 2 Octet core then we can allocate more than 16 VMs each VM 1 CPU but still I am not sure about CPU and RAM allocation for VM's like what is limitation and basic calculations

August 29th, 2015 12:24pm

For CPU, if you had a 2 socket server with 8 cores per socket, that's 16 logical processors. If you have Hyperthreading enabled, it's 32 logical processors. I think what you're asking is how many vCPUs can you have per logical processor? I don't believe there are any hard rules as it will vary depending on what you are running in the VMs. You'll be able to find guidelines saying in the region of 5 to 8 vCPU to each logical processor. But you'll need to monitor performance to find the best ratio in your environment. Couple of links: http://blogs.technet.com/b/virtualization/archive/2011/04/25/hyper-v-vm-density-vp-lp-ratio-cores-and-threads.aspx http://www.virtualizationadmin.com/articles-tutorials/microsoft-hyper-v-articles/general/maximizing-your-virtual-machine-density-hyper-v-part4.html You can find the details of limits for vCPUs per VM and per host here, but I don't think there is a limit on how many per core (other than performance will suffer): https://technet.microsoft.com/en-us/library/jj680093.aspx
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August 29th, 2015 2:47pm

thanks kindly some lights regarding physical RAM and virtual ram. usually we change virtual ram (1.5 times mores) so if logic in physical ram for e.g. I have 120 GB so I can assign 120 or 18 GB for 6 VM's? not more than that? VMware or Hyper V uses how many GM RAM
August 30th, 2015 3:47am

 VMWare allows you to over overcommit memory. Hyper-V does not.
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August 30th, 2015 5:55am

overcommit means what is maxuim? can you provide small example
August 30th, 2015 7:12am

Overcommit means trying to 10 pounds of content into a five pound bag.  Yes, VMware can do this, but they don't recommend it because it has a significant negative impact on performance.  If there is only 120 GB of physical memory, and you absolutely have to have 150 GB of memory to run the workload, that means things are going to get paged out of memory (very slow process) and sometimes the wrong things, such as kernel code, can get paged out.

Microsoft uses a concept called dynamic memory.  You can assign a range of memory to the VMs running on a host.  As a machine needs more memory, it will ask for it.  When it no longer needs it, it gives it back.  If it needs it and there is no more to give, i.e. you are trying to overcommit memory, it will fail in the request.

How well this works in your environment is completely unknown to us.  You need to monitor your particular requirements to see if it makes sense for you.

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August 30th, 2015 9:55pm

Microsoft uses a concept called dynamic memory means Hyper will supports more workload?Overcommit means trying to 10 pounds of content into a five pound bag.
September 3rd, 2015 11:02pm

"Microsoft uses a concept called dynamic memory means Hyper will supports more workload?"

No, dynamic memory does not mean Hyper-V will support more workload than VMware.  When all is said and done, the same physical hardware can support a very similar workload.  If you are trying to use every last byte of memory on either system, you will start to run into issues. 

Earlier, you were trying to get 6 20 GB VMs in 120 GB of physical memory.  In neither system is the calculation that straightforward.  In both cases, the hypervisor, Hyper-V or ESXi, requires the use of some of the physical memory.  That is not a fixed amount, but let's assume each of them needs about 2 GB.  Then in addition to the memory you assign to each VM, the hypervisor has to set aside 'management' space for each VM.  After all, the hypervisor is the authority on what physical memory gets mapped to what virtual machine.  So the hypervisor sets up tables in its memory to keep track of which VMs are using which physical memory.  Similarly, there is a mapping between the physical cores on the host and the virtual CPUs in the VMs.  More space in the hypervisor.  As a result, there is overhead associated with each VM created.  The last time I made the comparison, Hyper-V used less overhead per VM than did ESXi, so if you were trying to cram the absolute maximum number of small VMs onto a physical machine, Hyper-V stood a chance of getting maybe one or two more than ESXi.  But it is completely dependent upon the workload.

Your questions are very theoretical.  Either hypervisor will work.  Hyper-V is cheaper if you are running Windows Server VMs.  Each hypervisor has some things the other hypervisor does not have.  Trying to make a decision on a hypervisor based on a single hardware platform configuration is not a fruitful use of time.

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September 4th, 2015 10:41am

For CPU, if you had a 2 socket server with 8 cores per socket, that's 16 logical processors. If you have Hyperthreading enabled, it's 32 logical processors. I think what you're asking is how many vCPUs can you have per logical processor? my question will be "Hyperthreading enabled, it's 32 logical processors" how it will 32?
September 5th, 2015 2:18am

Hyper-V does not put a limit on the number of vCPUs per logical processor. That is completely dependent upon the application. Some applications do not like hyperthreaded logical processors, so you might want to turn that off on some Hyper-V hosts. Other applications work fine with hyperthreaded logical processors. Hyper-V has no way of telling what the application requirements are in regards to vCPUs to logical processor, so it does not enforce any limitation.

That's why I am saying so many of your questions are theoretical.  Hyper-V imposes very, very few constraints.  But once you put your own applications on the system, you are going to find that your applications create all sorts of constraints.  That has nothing to do with the hypervisor.

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September 7th, 2015 6:06pm

My question is if i am using 2 CPU with Octa core then 16 VCPU? second question HyperV / Vmware can i use up to 16 Virtually CPU or more than that?
September 10th, 2015 11:13pm

Hi Cabpeter,

If the VCPU you mentioned means the Virtual Processors of VM.

1. You can use more than 16.

2. In Hyper-V, in one VM, no more than 16. All VMs together, more than 16.

Best Regards,

Leo

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September 11th, 2015 7:13am

Under Windows Server 2008 R2 the recommendation was a Ratio from 8:1. Means 8 vCPUs on one Logical CPU. If you use Hyperthreading you have more than 16 Logical CPUs (not 2 x Octa (8)).

Under Windows Server 2012 there is no recommendation Ratio, only a natural
September 11th, 2015 7:42am

i am not understood kindly explain bit more if any difference between physical. logical, virtual CPU if yes what is difference second question hyper threading needs to enable in BIOS to support VM's ? third question what is formula or limitation of CPU in Vmware or Hyper V my assumption is if 2 CPU with Octa core means 16 Virtual CPU so we can use 16 CPU's I am right?
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September 12th, 2015 5:09am

Hi Cabpeter,

1, 3:

>>third question what is formula or limitation of CPU in Vmware or Hyper V my assumption is if 2 CPU with Octa core means 16 Virtual CPU so we can use 16 CPU's I am right?2 CPU: physical CPU. Octa core: logical CPU.

For one VM: no more than 16 Virtual CPU.

2:

Yes.

Best Regards,

September 13th, 2015 9:26pm

Honestly I am understand please explain with more details and answer to my all questions
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September 14th, 2015 1:27am

Hi Cabpeter,

Open Task Manager on host, then you could see the number of logical CPUs.

Open settings of VM, expand Processors, then you could see the number of virtual processors.

Of one VM, the number of virtual processors could not be larger than the number of logical CPUs. That means you can use 16 VCPUs.

Best Regards,

Leo

September 14th, 2015 2:11am

Thanks Please explain what is logic and virtual processor second question how to set logical processor third question if I have 2cpu with octaccor processor so how many logical and virtual processor fourth questions how much we use for guest vm

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September 14th, 2015 2:34am

Hi Cabpeter,

1. We could regard Logical CPU as the core of physical CPU. About the detailed principle, we could ask the manufacturer of the CPU. A virtual processor is more like processing time. The hypervisor takes the logical processors and chunks then into processing resources that are in turn used as they are needed. (According to BrianEH's post.)

2. It could not be set. It comes with physical CPU.

3. I have explained twice. 16 Logical CPUs. For one VM, no more than 16 Virtual Processors.

4. It depends on the hardware requirement of the guest OS.

Besides, it is better for reading and understanding if you could add punctuations between sentences please.

Best Regards,

Leo

September 14th, 2015 2:57am

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