If the processor does hyperthreading, VMware can allocate each virtual core. For example, I have an I7 and VMware sees 8 cores. I am not sure if VMware Player/Workstation are able to allocate a core only for the virtual machine. The allocated cores might be used by the host OS also. But... I am not sure. But there are other virtualising applications (made by VMware or others) which are used to create VPSs and they can allocate cores and memory only to be used by the specified virtual machines, so it should be possible. --Octavian ----- Original Message ----- From: "John G. Heim" <jheim@math.wisc.edu> To: "'Blind sysadmins list'" <blind-sysadmins@lists.hodgsonfamily.org> Sent: Thursday, November 15, 2012 10:38 PM Subject: Re: [Blind-sysadmins] cpu recommendation
Are you sure that if you start up a virtual machine with 2 virtual cores that it actually runs on 2 physical cores? I'm not sure how VMWare would manage that since I'd assume it would be up to the host operating system. Maybe there is some standard way for the host OS to let a piece of software specify that it be allocated to a certain number of physical cores. Get what I'm saying? How does VMWare workstation tell the linux kernel to letthe a virtual machine have two physical cores all to itself?
Plus, there is this concept of hyperthreading which allows a single core to act like 2 cores. So if you have a quad-core machine, it can act like an 8 core machine. But even that might not be the limit because every computer in the world can run an indefinite number of processes at once and a virtual machine is just another process. In other words,you can have multiple processors per machine, multiple cores per processor, multiple threads per core, and multiple processes per thread. So I don't know how many virtual cores you can have.
I've been told that you can run VMWare Workstation on a single-core machine. My source for that is not very reliable though. I gave away my machine with VMWare Workstation. I wish I had it right now. I'd just try starting up VMs with more cores than I actually have and see what happens.
From: Blind-sysadmins [mailto:blind-sysadmins-bounces@lists.hodgsonfamily.org] On Behalf Of Scott Granados Sent: Thursday, November 15, 2012 1:44 PM To: Blind sysadmins list Subject: Re: [Blind-sysadmins] cpu recommendation
I'm not sure about workstation, fusion definitely has controls for allocating work to cores. You can set per VM how many cores and how much memory to use. Whether the knobs do anything is another story, they seem to near as I can tell.
Anyway, put me down for +1 on an I7.. That's what I'd use.
On Nov 15, 2012, at 2:11 PM, John G. Heim <jheim@math.wisc.edu> wrote:
VMWare Workstation doesn't even need a dual-core CPU. But it can take advantage of a CPU with a hypervisor if it has one. Obviously, the more cores, the more the hypervisor can do. I am not 100% certan that if you have Workstation on a quad-core CPU, you can run your host OS and 3 VMs and have each run on its own core. I'm not sure it works that way. But I'd hope so. I know ESXI works that way.
I'll bet a dual-core Intel CPU would run a host OS and one VM faster than a quad-core AMD CPU. But its anybody's guess what would happen if you started up a second VM. I might be willing to live with it slowing down though the rare occasions where I start up more than one VM.
This is a home PC. I could end up doing almost anything on it. I do the usual sskype, email, web browsing. But I've done some parallelized coding. And then I still have some fantasies bout teaching myself something about Windows networking by creating several Windows virtual machines and networking them.
-----Original Message----- From: Blind-sysadmins [mailto:blind-sysadmins-bounces@lists.hodgsonfamily.org] On Behalf Of Scott Granados Sent: Thursday, November 15, 2012 12:07 PM To: Blind sysadmins list Subject: Re: [Blind-sysadmins] cpu recommendation
I'm an intel man myself. I like the I7 which I use in my Macs and on the server side we have some decent Xeon quad core stuff going on in some dell boxes.
Is the virtual machines / VMware the heaviest source of load, what else will you be doing with the box?
On Nov 15, 2012, at 12:39 PM, John G. Heim <jheim@math.wisc.edu> wrote:
I need to buy a new mobo, CPU, and RAM before December 31. Any recommendations on a CPU? I intend to run linux with Windows running in a VMWare Workstation virtual machine. Sometimes I run 2 or 3 vms at once so I'd prefer a qua-core CPU.
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