[Devel] Re: [PATCH 0/9] namespaces: Introduction

[John Kelly]

On Fri, 19 May 2006 11:28:08 -0700, "Hua Zhong" <hzhong at gmail.com>
wrote:

> how many virtualization technologies Linux should support?

> Particularly, does it need to support both OS-level virtualization

If users want it.  I do.


> It seems at least the VM approach is much less risky. It might be helpful
> if someone could explain why we need both.

A better question is, why can't we have both?

I don't have unlimited memory and disk.  I need to conserve my
resources as much as possible.

The one-kernel approach saves memory, leaving more for applications.
That's important to me.  I don't need to run multiple kernels, and I
don't want to.  I only want multiple secure operating environments.

The one-kernel approach also makes it easy to have all VPS in one disk
partition, without the performance penalty of file backed I/O.

If the VM approach is truly less risky, seems to me the Xen/VMware
developers should be able to succeed independently, despite changes
made for in-kernel virtualization.

I'm glad someone asked a question I could answer.  :-)