Best small footprint host OS I could install on a laptop dedicated to just running VMs?

Question

Saw this question and it got me thinking: Is it possible/advisable to run VMware Server ESX/ESXi on a laptop?

Clearly running ESX directly on the laptop metal is not going to work, however I find I do most of my work inside VMWare Workstation and ideally I'd like my base OS to use as little cpu/ram/disk io as possible so my VMs can perform better.

I have found things like TinyXP that would suit me - unfortunetely this is not really legal.

Is there any recommended linux distro with this sort of application in mind? Or can I strip Win7 down to the bones? Win Server 2003/2008 worth looking at?

64 bit would be nice but I'm not sure its essential.

edit: my VMs are mainly windows with and the odd linux 'development appliance' preloaded with LAMP or similar.

Answer 1

I've run Win Server 2008 R2 on a laptop for exactly this purpose before, and it worked fine. Just be sure you mean it when you say that this laptop is "just for" running VMs, because once Hyper-V is enabled, the audio and graphics performance on the parent partition's local console will pretty much suck.

With pretty much everything but Hyper-V turned off, the OS only used about 512MB of RAM (on average). The forthcoming Dynamic Memory feature in SP1 will make scenarios like this even more feasible, as they allow you to oversubscribe the host's RAM and squeeze more VMs onto the laptop.

In my experience, the real performance bottleneck for VMs on laptops isn't the hypervisor -- it's the disk drive. Storing your VMs on an external hard drive is a good way to both improve performance and make your VMs easily portable between machines.

Hope this helps!

Answer 2

To get the best VM performance you'd need to either run VMWare on the bare metal or try Windows 2K8R2 with the Hyper-V role enabled. I've never played with ESX so I can't comment on that. With enough horse power you should be able to run 2K8R2 though. Maybe a Dell E6510 with a hyper threaded quad core and 8GB RAM. The bottle neck will be disk access regardless of what solution you come up with. An SSD may help.

I see VMWare has something called VMWare Workstation. https://www.vmware.com/products/workstation/

Answer 3

VMWare is nice - however you still need to get into the hypervisor somehow - and that can prove difficult if you don't know the CLI or have another system handy to do so.

Approaches to Virtualization (linux)

There are many different approaches to virtualizing a system, each with their own advantages and disadvantages.

Paravirtulization:

In a nutshell, In order to run more efficiently, the guest operating system's kernel is changed out for a kernel that behaves well in a virtualized environment.

Xen, lguest and User Mode Linux do paravirtualization on x86.

Hardware Virtualization

Intel VT and AMD-V CPUs have the ability to run all instructions in an unprivileged virtual machine, and have them behave well. Most of the time much of the resources are emulated (like the clock) However, it allows for a much cleaner implementation of full virtualization.

Xen and KVM do hardware assisted full virtualization.

Operating-System level virtualization - (Containers)

Containers do not run virtual machines at all, but simply segregate multiple user space environments from each other, while everything runs under one kernel. (One major reason many system administrators lvoe this is because they only ever need to patch or maintain 1 kernel vs many.) Container systems tend to have low overhead and high density, but also lower isolation between the different containers. This of course comes at a cost - as container systems only allow 1 kernel running - however they do support various Linux distributions in the different containers at the same time. There are a number of different Container systems - such as Solaris Zones, Linux-VServer and OpenVZ/Virtuozzo. OpenVZ has relatively complete resource isolation between the different containers, the other two have a bit less control. FreeBSD Jails can be seen as a precursor to containers - however Jails of course or make that BSD is not Linux.

Hopefully this helps give you a simple breakdown of Linux virtualization.

IN YOUR CASE I WOULD SUGGEST SOMETHING RUNNING CONTAINERS _ UNLESS YOU REQUIRE WINDOWS:

I would suggest peeking at the Proxmox Project http://www.proxmox.com/products/proxmox-ve It is opensource - and will allow you to test not only KVM but also Container based virtualization on the same system at the same time.