Subject: Re: [vserver] Pros and Cons of 32/64bit guests on 64bit host
From: Herbert Poetzl <herbert@13thfloor.at>
Date: Fri, 22 Aug 2008 04:39:57 +0200

On Fri, Aug 22, 2008 at 10:32:39AM +0800, Stephen Liu wrote:
> Hi Ed,
> 
> I'm testing OpenVZ/vserver/VMware/Kvm/qemu respectively on their own
> PC.  This thread attracts my interest.  I'm considering building a
> quadcore PC with 8G RAM to test this idea running several VMs on same
> PC.  Interesting!!!
> 
> 
> --- Ed W <lists@wildgooses.com> wrote:
> 
> - snip -
> 
> > So you kind of allocate XYZ MB to each virtual machine
> > and 
> > you roughly have to live with that commitment
> 
> 
> Please explain in more detail.  On installing the software of virtual
> machine they don't request alloting XYZ MB RAM.

you have a 'kernel' per guest, and all the 
resources, like files or memory cannot be
shared between virtual machines, thus if you
have 10 machines running you will use 10 times
the resources as if one machine (real or virtual)
is running 

> > Since the former are kind of complete machine emulations I would
> > assume 
> > it's no problem to run vserver under a kvm/vmware image.  
> 
> 
> If I understand your advice correct I can install vserver on the guest
> running on KVM/VMware image?  A virtual machine on another virtual
> machine?
> 
> 
> > On the other 
> > hand there is no way to run Windows under a vserver image since it's 
> > really just a fancy chroot system (plus some other features)
> 
> 
> I can't install Windows on OpenVZ.  I have no idea whether it works on
> vserver.  On installing Vista Ultimate on KVM I encountered some

the project name is Linux-VServer and I hope that
answers your question, if not, the technology
is based on OS level virtualization, which means
it uses a shared kernel, instead of virtual machines

as long as Windows(tm) doesn't use a Linux kernel
it won't be supported :)

the advantage of OS level isolation/virtualization
is that you only need a fraction of the resources
than for full virtualization, which allows you
to run hundreds of guests inside a recent machine

best,
Herbert

> problem.  I can't start it on next boot without putting its installer
> on CDRom.  Otherwise it will be dropped to rescue mode.  I read a
> document on Internet suggesting installing XP first, stopping after
> partitioning and continue installing Vista Ultimate.  I'll test this
> suggestion later when I have time.
> 
> 
> Others noted with thanks
> 
> 
> B.R.
> Stephen
> 
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