Subject: Re: [vserver] Pros and Cons of 32/64bit guests on 64bit host
From: Stephen Liu <satimis@yahoo.com>
Date: Fri, 22 Aug 2008 21:21:23 +0800 (CST)

Hi Herbert,


Thanks for your advice.


--- Herbert Poetzl <herbert@13thfloor.at> wrote:

> > 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 


If I have 4 virtual machines running on the same box simultaneously I
need 4 times the resources calculated on each virtual machine running
on its own box.  Then it needs a powerful PC, at least 2 quadcore CPUs
with >8G RAM onboard.  I have no idea about max RAM able to run on a
server motherboard.  I'll do some search later.

How about the guests?  They also consume resource.  Thanks.


> 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


Noted and thanks.


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


Noted with thanks.  It is not a serious matter to me.  I use them for
test only NOT for production.  What about Windows servers?  Can they
run on OS level virturalization?


> 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


It sounds wonderful hundreds of guests running on one powerful PC. 
I'll run them as daemons.


I have following 2 thoughts to consider.

1)
If the PC is down because of hardware failure then hundreds of server
will be down.  It needs a well established replication and load
balancing.


2)
It needs a range of fixed/public IP address serving hundreds of server
on the Virtual box.  I'm investing whether there will be a way to
overcome this difficulty.  Each server has its own hostname and domain.
 If hundreds of domain pointing to one fixed/public IP address is there
a device able routing them to respective server.  I have been posting
this question on Vyatta forum without response.  Are there any
suggestions?  TIA


B.R.
Stephen





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