Vmware Processor & Core

If I have a machine with 2 CPU (Xeon) duel core... 12 GB Memory. Also assume I setup each machine each with 4GB duel core. The max machines the vmware can run is 2 because I am limited by the cores. Is that correct?
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As above, use ESXi, as it uses far less resources than the host OS that is running VMware Workstation. So with ESXi you can run more VM's simultaneously. Basically it depends on the OS your VM's will use. Many Linux Distro's use less RAM than Windows VM's do. Besides that it also depends on how the VM's are used. If They are more or less idling along, you can run more at the same time, as the memory is released for other VM's. But if they are heavily used you won't be able to run as much simultaneously. Basically the VM's require the same amount of RAM as they would as physical PC's.
Mohammed KhawajaManager - Infrastructure:  Information TechnologyCommented:
No, that is not correct.  You can over provision and it could result in slow performance.
No. You can theoretically run many more VM's simultaneously. The HyperVisor presents Virtual CPU/Cores to the VMs, and manages what CPU or Core Processes which tasks from which VM.
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Yes, you can have many VM and they will share the CPU cores.
The most limiting thing could be the 12Go RAM in your case. But for 2 or 3 machines it should be OK.
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
You should be able to allocate more sockets than that per VM....BUT Wait do you need to....?

vSMP (virtual SMP) can affect virtual machine performance, when adding too many vCPUs to virtual machines that cannot use the vCPUs effectly, e.g. Servers than can use vSMP correctly :- SQL Server, Exchange Server.

This is true, many VMware Administrators, think adding lots of processors, will increase performance - wrong! (and because they can, they just go silly!). Sometimes there is confusion between cores and processors. But what we are adding is additional processors in the virtual machine.

So 4 vCPU, to the VM is a 4 Way SMP (Quad Processor Server), if you have Enterprise Plus license you can add 8, (and only if you have the correct OS License will the OS recognise them all).

If applications, can take advantage e.g. Exchange, SQL, adding additional processors, can/may increase performance.

So usual rule of thumb is try 1 vCPU, then try 2 vCPU, knock back to 1 vCPU if performance is affected. and only use vSMP if the VM can take advantage.

Example, VM with 4 vCPUs allocated!

My simple laymans explaination of the "scheduler!"

As you have assigned 4 vCPUs, to this VM, the VMware scheulder, has to wait until 4 cores are free and available, to do this, it has to pause the first cores, until the 4th is available, during this timeframe, the paused cores are not available for processes, this is my simplistic view, but bottom line is adding more vCPUs to a VM, may not give you the performance benefits you think, unless the VM, it's applications are optimised for additional vCPUs.

See here

see here


also there is a document here about the CPU scheduler


Starquest321Author Commented:
I have a dell poweredge t110 with 8MB :: 500 GB :: XEON QUAD CORE.

1. Around how many machines can this safely run?
2. SHould I install ESX on it .. and then load machines or should I use Windows 7 and then workstation?
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
With 8GB of RAM, you will be limited by MEMORY!

We run approx 5-6 VMs per Core on physical servers, but MEMORY will always be the bottleneck, so you could run 8 x 1GB VMs, or 2 x 4GB VMs, BUT you need at least 2GB free for the Hypervisor.

So the answer is not many VMs, without upgrading the memory to at least 16 or 32GB.

VMware Workstation is a Type 2 Hypervisor, compared to ESXi.
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