CentOS - Mar 2011 - virtualization on the desktop a myth, or a reality?

I am busy setting up some XEN servers on a SAN for high availability
and Cloud Computing, and thought it could be cool to setup
virtualization on a CentOS 5.5 Desktop, running on a Core i3 + 4GB
RAM, and use the SAN's storage to see if it could actually be worth my
while to replicate a Cloud Computing setup in the office. And, cause I
got a bit bored waiting for a few RAID-sets to finish initializing.

So, I installed CentOS + KDE, chose the Virtualization package and
used Virtual Machine Manager to setup another CentOS VM inside CentOS
(I only have a CentOS ISO on this SAN, since we don't use Debian /
Slackware / FC / Ubuntu / etc). The installation was probably about
the same speed as it would be on raw hardware. But, using the
interface is painfully slow. I opened up Firefox and browsed the web a
bit. The mouse cursor lagged a bit and whenever I loaded a slow /
large website, it seemed asif the whole VM lagged behind.

The Virtual Machine didn't use much resources. I allocated 1CPU core &
512MB RAM to it

Yes, I know that I could have used KVM, VMWare or VirtualBox, but I
wanted to use what's included already. Cause, let's face it, many
people (even though they're technically advanced users) don't know
virtualization.

And, granted, when we install Virtual Machines on a XEN server, we
don't ever use X since the servers we run as web / email / database /
file servers, so there's no need for X.

BUT, I want(ed) to see if this is a reality for the average desktop
user, or not really (yet?) seeing as most modern PC's have far more
CPU & RAM resources than what is actually needed by most. I'm not
talking about developers / graphic designers / etc. I'm talking about
Bob, who uses his PC for email, internet, document writing, etc and
needs to boot into Windows if he feels like playing Warcraft III or
StarCraft II, or use Pastel, etc.

Wouldn't it be nice to run Windows, of for that matter Solaris /
FreeBSD / MAC (graphics designer) / another flavor of Linux / etc
inside your favorite Linux, and access it from the Desktop without too
much trouble?




-- 
Kind Regards
Rudi Ahlers
SoftDux

Website: http://www.SoftDux.com
Technical Blog: http://Blog.SoftDux.com
Office: 087 805 9573
Cell: 082 554 7532

>Yes, I know that I could have used KVM, VMWare
>or VirtualBox, but I wanted to use what's included already.
KVM is included, you just have to select it. There is a loyal following of
Xen in the community, but I use KVM for my servers. I'm often called
'dumb'
for even talking about KVM, but I like it. (and I'm not saying, nor have I
ever said, that KVM is better than Xen)

> But, using the interface is painfully slow. I opened up Firefox
>and browsed the web a bit. The mouse cursor lagged a bit and
>whenever I loaded a slow /large website, it seemed asif the whole
>VM lagged behind...
>.. BUT, I want(ed) to see if this is a reality for the average desktop
>user, or not really (yet?) seeing as most modern PC's have far more
>CPU & RAM resources than what is actually needed by most.
I assume you're using VNC to connect? It can be painfully slow with some vnc
clients, and workable for basic stuff with others.

Using MS remote desktop to connect to a VM running Windows works pretty
well, but not when you're trying to view anything with graphics. (like
watching videos)

There's the SPICE protocol which supposedly handles these problems, although
I haven't tried it yet.

It would be nice if you could run your OS in a VM, then use some tablet with
a huge screen to connect to the VM and not be able to notice a difference in
speed. I think that's a ways off in the future, however.

On 3/2/2011 11:29 AM, Rudi Ahlers wrote:
>
> So, I installed CentOS + KDE, chose the Virtualization package and
> used Virtual Machine Manager to setup another CentOS VM inside CentOS
> (I only have a CentOS ISO on this SAN, since we don't use Debian /
> Slackware / FC / Ubuntu / etc). The installation was probably about
> the same speed as it would be on raw hardware. But, using the
> interface is painfully slow. I opened up Firefox and browsed the web a
> bit. The mouse cursor lagged a bit and whenever I loaded a slow /
> large website, it seemed asif the whole VM lagged behind.
X without hardware acceleration is pretty ugly - you end up making the 
CPU do block moves even for simple things like screen scroling.  Not 
sure how how the virtual interface works, but a better approach is 
either running X natively on your local hardware with the desktop/app 
remote (if you are on a low latency LAN) or freenx on the server and the 
NX client locally (works regardless of the connection speed).
> And, granted, when we install Virtual Machines on a XEN server, we
> don't ever use X since the servers we run as web / email / database /
> file servers, so there's no need for X.
Xen seems to be on its way out.
> BUT, I want(ed) to see if this is a reality for the average desktop
> user, or not really (yet?) seeing as most modern PC's have far more
> CPU&  RAM resources than what is actually needed by most. I'm not
> talking about developers / graphic designers / etc. I'm talking about
> Bob, who uses his PC for email, internet, document writing, etc and
> needs to boot into Windows if he feels like playing Warcraft III or
> StarCraft II, or use Pastel, etc.
If you have paid for a windows license and/or want to run games, why 
wouldn't you run Windows natively, with the NX client to access remote 
linux desktops, or VMware Player to run it locally.
> Wouldn't it be nice to run Windows, of for that matter Solaris /
> FreeBSD / MAC (graphics designer) / another flavor of Linux / etc
> inside your favorite Linux, and access it from the Desktop without too
> much trouble?
Yes, as a matter of fact, it is nice - but it doesn't really make much 
difference which is the host and which is the guest, or for most things 
whether you run locally or remotely.  For most things, I find floating a 
running Linux desktop around among NX clients to be extremely handy. 
And, if you want a local VM, it is possible to set a dual-boot system up 
so you also have a choice of running the currently-inactive partition 
under vmware player without rebooting.

-- 
   Les Mikesell
     lesmikesell at gmail.com

On Wed, 2 Mar 2011, Rudi Ahlers wrote:
> I am busy setting up some XEN servers on a SAN for high availability 
> and Cloud Computing, and thought it could be cool to setup 
> virtualization on a CentOS 5.5 Desktop, running on a Core i3 + 4GB 
> RAM [...]
>
> So, I installed CentOS + KDE, chose the Virtualization package and
> used Virtual Machine Manager to setup another CentOS VM inside CentOS
> (I only have a CentOS ISO on this SAN, since we don't use Debian /
> Slackware / FC / Ubuntu / etc). The installation was probably about
> the same speed as it would be on raw hardware. But, using the
> interface is painfully slow. I opened up Firefox and browsed the web a
> bit. The mouse cursor lagged a bit and whenever I loaded a slow /
> large website, it seemed asif the whole VM lagged behind.
>
> The Virtual Machine didn't use much resources. I allocated 1CPU core
&
> 512MB RAM to it
I've never allocated less than 1 GB RAM to a VM with an active GUI, 
but I suspect that RAM crunch is part of the problem.

Install CentOS 5 on raw hardware with 512 MB RAM and try running 
Firefox...

-- 
Paul Heinlein <> heinlein at madboa.com <> http://www.madboa.com/

On 3/2/2011 2:06 PM, Rudi Ahlers wrote:
>
>>> Differently put, we already do this with servers. One big&   
fast Quad
>>> XEON can run many client's Virtual Machines, very easily. And
many of
>>> those Virtual Machines host a few hundred websites, thus saving a
lot
>>> on rack space, electricity, etc, etc.
>>
>> Servers are normally optimized with lots of disk spindles to spread
>> multi-user use of the one remaining slow resource around.
>
> True, but in a one-user-one-drive (or 2 drives in RAID1) setup, the
> disk I/O wouldn't be a problem, or the limiting factor.
I thought some of your scenarios involved doing things in both os's at 
once.  Which will make them want the disk head to be in different places 
at the same time.
>> Give the VM its own disk and it won't have much impact on the host.
>> You'll probably still want to run video-intense things natively,
though.
>>   And if you aren't a developer doing throwaway tests, what's
the point
>> of using a VM for resource-intensive things anyway?
>
>
> There are many reasons why one would do this kind of things. Just
> thinking of my normal day-to-day work, I often start-up a new VM to
> test certain functionality of some software package, without affecting
> anything on my PC.
If it is at work, why not park the VM on a server that is probably 
better equipped?
> My laptop runs Windows 7 at this stage, purely for
> Quickbooks and a few other Windows-only applications. So, in this case
> it would be nice to have Windows running permanently on my PC which
> will allow the accounts person to still access it remotely on her PC
> and I can still do stuff in Quickbooks as needed. But, I would prefer
> real-time access.
Then why not run it as the host?  It probably handles sleep mode and 
waking up on different networks better than Centos anyway.  Or as a VM, 
park it on a server where everyone who needs access can reach it remotely.
> I think the major problem here is that the tools at hand, i.e. XEN +
> Virtual Machine Manager (or for that matter VirtualBox / VMWare / etc)
> isn't yet optimized for this kind of usage.
>
> I guess we need better VGA-passthrough drivers, and / or a more
> optimized interface. Accessing the VM's via VNC / Remote Desktop / XN
> / etc is also probably also a possibility.
Have you tried vmware player with vmware tools installed in the guest 
for comparison?  Or NX connecting to freenx in the case of a Linux guest?

-- 
   Les Mikesell
    lesmikesell at gmail.com

On Mar 2, 2011, at 12:29 PM, Rudi Ahlers <Rudi at SoftDux.com> wrote:
> I am busy setting up some XEN servers on a SAN for high availability
> and Cloud Computing, and thought it could be cool to setup
> virtualization on a CentOS 5.5 Desktop, running on a Core i3 + 4GB
> RAM, and use the SAN's storage to see if it could actually be worth my
> while to replicate a Cloud Computing setup in the office. And, cause I
> got a bit bored waiting for a few RAID-sets to finish initializing.
> 
> So, I installed CentOS + KDE, chose the Virtualization package and
> used Virtual Machine Manager to setup another CentOS VM inside CentOS
> (I only have a CentOS ISO on this SAN, since we don't use Debian /
> Slackware / FC / Ubuntu / etc). The installation was probably about
> the same speed as it would be on raw hardware. But, using the
> interface is painfully slow. I opened up Firefox and browsed the web a
> bit. The mouse cursor lagged a bit and whenever I loaded a slow /
> large website, it seemed asif the whole VM lagged behind.
> 
> The Virtual Machine didn't use much resources. I allocated 1CPU core
&
> 512MB RAM to it
> 
> Yes, I know that I could have used KVM, VMWare or VirtualBox, but I
> wanted to use what's included already. Cause, let's face it, many
> people (even though they're technically advanced users) don't know
> virtualization.
> 
> And, granted, when we install Virtual Machines on a XEN server, we
> don't ever use X since the servers we run as web / email / database /
> file servers, so there's no need for X.
> 
> BUT, I want(ed) to see if this is a reality for the average desktop
> user, or not really (yet?) seeing as most modern PC's have far more
> CPU & RAM resources than what is actually needed by most. I'm not
> talking about developers / graphic designers / etc. I'm talking about
> Bob, who uses his PC for email, internet, document writing, etc and
> needs to boot into Windows if he feels like playing Warcraft III or
> StarCraft II, or use Pastel, etc.
> 
> Wouldn't it be nice to run Windows, of for that matter Solaris /
> FreeBSD / MAC (graphics designer) / another flavor of Linux / etc
> inside your favorite Linux, and access it from the Desktop without too
> much trouble?
When I had Xen setup on my desktop with 4GB I setup dom0 with 1GB running X
display manager xdm/kdm/gdm and ran headless X in each domU, 1GB for each VM. I
then had a selection dialog on my X session in dom0 for which host to log in to
and a full X session for that distribution.

Sound is the only tricky part, you need a sound server in dom0 that allows sound
from all VMs.

This works with Xen or KVM, though the management and compartmentalization of
Xen helps.

Does CentOS support the shared memory pages, memory dedup, in Xen? That would
allow for a lot more Linux VMs.

-Ross

On Wed, 2011-03-02 at 19:29 +0200, Rudi Ahlers wrote: 
> I am busy setting up some XEN servers on a SAN for high availability
> and Cloud Computing, and thought it could be cool to setup
> virtualization on a CentOS 5.5 Desktop, running on a Core i3 + 4GB
> RAM, and use the SAN's storage to see if it could actually be worth my
> while to replicate a Cloud Computing setup in the office. And, cause I
> got a bit bored waiting for a few RAID-sets to finish initializing.
> So, I installed CentOS + KDE, chose the Virtualization package and
> used Virtual Machine Manager to setup another CentOS VM inside CentOS
> (I only have a CentOS ISO on this SAN, since we don't use Debian /
> Slackware / FC / Ubuntu / etc). The installation was probably about
> the same speed as it would be on raw hardware. But, using the
> interface is painfully slow. I opened up Firefox and browsed the web a
> bit. The mouse cursor lagged a bit and whenever I loaded a slow /
> large website, it seemed asif the whole VM lagged behind.
I have openSUSE 11.3 GNOME desktop instances in VMware ESX... works
great and performance is good.
> Wouldn't it be nice to run Windows, of for that matter Solaris /
> FreeBSD / MAC (graphics designer) / another flavor of Linux / etc
> inside your favorite Linux, and access it from the Desktop without too
> much trouble?
Do this every day from my openSUSE 11.3/GNOME laptop; accessing openSUSE
11.3/GNOME instance on ESX as well as a Windows Vista instance in local
VMware Workstation.  Works great, performance is good.

I only have CentOS instances as servers (all in VMware ESX... and, of
course, performance is very good).

On Thursday, March 03, 2011 01:20:06 pm Dr. Ed Morbius
wrote:
> Compare against CIFS/Samba shares or NFS exports bewteen booted
> host/guests.  You get native filesystem support (under the host/guest as
> relevant), and mappings via CIFS/Samba and/or NFS/NIS+.
> 
> The win is still virtualization.
There are situations where dual-booting is a necessary thing to do; one of those
is low-latency professional audio where accurate timekeeping is required;
basically anything that needs the -rt preemptive kernel patches.  I actually
have need of this, from multiple OS's, and while I've tried the 'run
it in VMware' thing with Windows and professional audio applications the
results were not satisfactory.

There are commercially developed and supported drivers for cross-platform uses
put out by Paragon Software; ext[234]fs on Windows and OS X, HFS+ on Linux and
Windows, and full NTFS (with lots of utilities) on OS X and Linux.

HFS+ would be the preferred filesystem to interchange with Mac OS X, but the
in-kernel Linux drivers for HFS have issues; if it's for read-only it's
not a problem, but the in-kernel driver is unsafe for anything like a heavy
load, with filesystem corruption possible especially when deleting lots of small
files.

On Thursday, March 03, 2011 03:55:48 pm Les Mikesell
wrote:
> But you can usually run the one that is picky as the host OS and the 
> other(s) virtualized.  
You really don't know what you're talking about in this case, Les.  The
specific machine that I'm talking about needs access to Harrison Mixbus on
OS X with iZotope Alloy, Ozone, and Spectron as AudioUnits, and also access to
Ardour (soon Mixbus, once I get some things squared) on Linux with certain
specialized LV2 plugins for special tasks.  Both environments are time critical.
There is also clock sync to outboard processing gear; I'm talking realtime
on both OS'es, and virtualization is not a workable option, at least as long
as hard realtime under a VM isn't possible.  If the iZotope plugins would
work as VST's under Linux in a reliable manner I could remove at least part
of my need for OS X; well, and once Melodyne for Windows can run under Crossover
(haven't tried; don't know).  But I still do analysis in Spectre, and
that's OS X-only.
> Or set up for dual boot, but give your virtual 
> machine direct access to the partition (VMware can do this - not sure 
> about the others).  Then you only have to boot into the other OS when 
> you need to run the specific app that doesn't work well in a VM.
Again, there are apps on both systems that are needed, and they need to share
rather large audio files (multiple tracks of 32-bit floating point audio for
many minutes means a number of GB per session).  And due to outboard processing,
clock sync is a must; in the future, SMPTE timecode will be part of that.  And
since the workflow between the two operating systems *is* serializable, dual
boot is workflow-friendly in this environment, where you might be charging a
client significant amounts per hour of time.  And it wasn't too awfully hard
to set up.

And OS X running in VMware Workstation under Linux is rather difficult to do,
using direct partition access.  Linux/CentOS on VMware Fusion works great, but
VMware's timekeeping isn't.
> As long as you have access to a network, just connect up a common 
> nfs/samba share from some other machine.
No.  That specific machine is not networked, to reduce IRQ load.  Every IRQ that
can be turned off is turned off.

On Thursday, March 03, 2011 04:04:42 pm Rudi Ahlers
wrote:
> Although it's not there yet, I'm sure we'll get there sooner
than expected
To be fair to VMware Fusion on OS X, the graphics acceleration is fantastic,
running Windows 7 in full Aero mode with no problems.  But it still can't
keep accurate time.

On Thursday, March 03, 2011 04:44:58 pm Les Mikesell
wrote:
> So there are actually apps that work in Linux that aren't available for
> OS X?
Yep.  For one example, there are the LinuxDSP plugins.  There are others. 
> I'm kind of surprised that a local disk controller would be better in 
> that respect than a network card.
Can be, depending upon the controller's chipset.  Networking has somewhat
non-deterministic characteristics, even for small networks.  And, if you
don't need networking to get the job done, why have it?

And don't believe what the IRQ-steering docs say; sharing IRQ's with
audio interfaces in not going to be reliable (been there, done that, got the
ALSA xruns to prove it), at least not the last time I tried it.  By cutting out
devices completely that need IRQ's, you can gain some control over what IRQ
goes where, in terms of the physical PCI slot, that leaving interfaces enabled
'Just Because' will complicate.  In one specific example, disabling the
ethernet interface on the motherboard of one particular machine, along with some
of the other devices like the onboard sound card and modem, I was able to get
the video card (nVidia) off the IRQ the audio interface's PCI slot (newer
motherboard; only one regular PCI slot in a location conducive to the audio
interface) had to have....