Hi Todd,
Thanks for your reply. I am after something that will
provide more than just a chroot-based environment for the VPS. Virtuozzo/OpenVZ
is effectively a chroot environment if you look at its filesystem structure.
The CPU will have Virtualisation Technology and 64bit
capability which is why I am exploring a full virtualisation type of setup
rather than a chrooted one.
With a LVM partition setup, I assume I can use the LVM
tools to easily resize a partition/filesystem to cater for more space/less
space needed on a certain VPS?
-Alan
-----Original Message-----
From: Todd Deshane [mailto:deshantm@xxxxxxxxx]
Sent: Thursday, 7 August 2008 11:50 AM
To: Alan Lam
Cc: xen-users
Subject: Re: [Xen-users] Xen Setup
On Wed, Aug 6, 2008 at 11:56 AM, Alan
<alan@xxxxxxxxxxxxx> wrote:
> Hi All,
>
>
>
> I am interested in deploying Xen to replace an
existing Virtuozzo based
> virtual server solution we are currently using.
However due to the
> differences in how it works etc., I would like some
clarification on our
> proposed setup:
>
>
>
> Firstly, what is the recommended OS for running Xen?
We are thinking of
> using 32bit CentOS 5 as the dom0 OS and probably
CentOS 5 domUs as well.
>
CentOS base and CentOS guests are well-supported and
known to work.
There really isn't a recommended OS, it is more a matter
of preference.
It may also matter what support, applications or
scenarios you hope to
achieve, but more likely it is a matter a preference.
>
>
> Secondly, due to using a 32bit OS, technically we'd
be limited to using 4GB
> ram in the server but I have read Xen is capable of
utilising PAE on 32bit
> systems to utilise more than 4GB ram. So in this
case, we would like to use
> 8GB of ram to split up amongst the Xen VPSes. Will
this be fine? Or will Xen
> not utilise the full 8GB available?
>
>
Xen 32bit + PAE on CentOS supported up to 16 GB of
RAM last I heard and
saw in the CentOS virtualization docs.
Xen will reserve a small amount for the management domain
and the hypervisor
itself, the rest can be used for guests.
>
> Lastly, we need to be able to "upgrade"
and "downgrade" a VPS's disk space
> easily. Under Virtuozzo all we need to do is change
the number of disk
> blocks allocated and reboot the VPS. Can we do
something similar with Xen,
> for instance using LVM partitions? I have read you
can either allocate a
> normal non-LVM partition, a LVM partition or a file
based partition as the
> "disk" for the VPS. I am looking for a way
to easily increase or decrease
> the space a VPS has without having to be fiddling
with partition tables and
> resizing manually using fdisk.
>
>
Xen can work similarly with LVM partitions.
I am curious about the application load, is it disk
intensive?
Also, are you switching to Xen to gain performance
isolation properties?
For simply pure performance I would expect openVZ to be
better in general,
but if you need the isolation properties and performance,
then Xen is a good
choice.
Hope that helps,
Todd
--
Todd Deshane
http://todddeshane.net
check out our book: http://runningxen.com
