CentOS virt - Apr 2009 - WinXP Xen guest: compare VNC vs RDP

I'm experimenting with using WinXP Xen guests as an alternative to 
upgrading workstations.  The administrative advantages seem overwhelming.

  Please share thoughts about using VNC vs RDP for remote desktop 
connections.

  Please share any anecdotal information regarding user reactions and/or 
implementation issues.

Ed Heron wrote:
>   I'm experimenting with using WinXP Xen guests as an alternative to 
> upgrading workstations.  The administrative advantages seem overwhelming.
> 
>   Please share thoughts about using VNC vs RDP for remote desktop 
> connections.
> 
>   Please share any anecdotal information regarding user reactions and/or 
> implementation issues.
> 
I use RDP because it allows copy & paste of text between the local and 
remote machines.  VNC does not, unless I've just not got it set up right.

- Julian

> I'm experimenting with using WinXP Xen guests as an alternative to 
>upgrading workstations.  The administrative advantages seem overwhelming.
Using the beta opensource parvirt drivers? Performance would be unacceptable
otherwise. On that note, my environment would not permit the unstable nature
of such an exercise...
>  Please share thoughts about using VNC vs RDP for remote desktop 
>connections.
RDP will be way faster, not to mention using vnc provides access to the
console which won't have video performance needed.
>  Please share any anecdotal information regarding user reactions and/or 
>implementation issues.
There's nothing cooler than Xen, but IMHO opinion I would be using something
a bit more stable for Windows guests, it's not the right tool for
>this< job
as far as I am concerned.

YMMV

On 04/22/2009 10:35 PM, Ed Heron wrote:
>   I'm experimenting with using WinXP Xen guests as an alternative to 
> upgrading workstations.  The administrative advantages seem overwhelming.
>
>   Please share thoughts about using VNC vs RDP for remote desktop 
> connections.
>   
I had to create 6 windows XP instances for a project a couple of months 
ago. Here are our conclusions, now that the project is over and the VMs 
have been decommissioned:
- XP was MUCH faster in Xen, compared to real hardware (!)
- RDP beats VNC in terms of speed any time, any place. I cannot evaluate 
precisely the factor, but empirically I'd say that in our conditions 
(WAN link, 6 Mbps upstream link on one site shared with other projects,  
100 Mbps on the other site) it was at least 2-3 times faster.
- rdesktop ( the linux app) is really cool, as it allows you to 
share/transfer local resources to the remote XP session (for instance 
you can map a local directory as a remote networked disk, without the 
hassle of passing via Network Neigh.). VNC forces you to either 
explicitly map such resources (hence you would also need something like 
samba on the linux side) or use scp.
- the only problem with RDP is that by default Windows limits the number 
of simultaneous connections. but patches do exist (which violate the 
licensing/usage terms, so beware).

As of implementations issues .. I had two (or should I say three?) problems:
- one is detailed in an older thread on this list ( look for "Using the 
parallel port from domU", 02/02/2009).
- second is due to Xen creating a large file with the same size as the 
disk given to the VM. I would have believed that sparse files would have 
been used, but df showed the opposite. I have seen 20 GB of space 
allocated, despite XP only using less than 5.
- last issue did not occur with stock Xen but with v3.3: Java inside the 
VM went nuts and starting consuming 99% of the processor.. while doing 
nothing. Once we reverted to stock Xen from C5.2, it went back to normal.

From: "Joseph L. Casale", Wednesday, April 22, 2009 4:23 PM
>> I'm experimenting with using WinXP Xen guests as an alternative to
>>upgrading workstations.  The administrative advantages seem
overwhelming.
>
> Using the beta opensource parvirt drivers? Performance would be 
> unacceptable
> otherwise. On that note, my environment would not permit the unstable 
> nature
> of such an exercise...
  Actually, no.  I'm using the fully virtualized guest.  My test virtual 
machine server is a Dell PowerEdge 2900 with dual-core Xeon with stock 
CentOS 5.  It only runs at 2Ghz, but I'm finding acceptable performance for 
the standard business applications that my users will run.  The system can 
go up to 2x4 core Xeons running at 3.33Ghz or something.  Ram can go up to 
48G and it has the option of 2 banks of 4 slots for hotswap hardware RAID. 
I'm hoping to be able to run about 12 virtual XP boxes on a 2900 with 8 x 
3Ghz cores and 16G RAM.

  My current workstations are 1.6Ghz Celerons with 512M to 1G RAM.  They are 
only running Outlook Express, Internet Explorer and a couple of proprietary 
applications.

  If paravirtualization drivers for WinXP ever become stable, that'd improve
performance and probably increase the number of WinXP VM's quite 
substantially.
>>  Please share thoughts about using VNC vs RDP for remote desktop
>>connections.
>
> RDP will be way faster, not to mention using vnc provides access to the
> console which won't have video performance needed.
  Have you done any real world like testing?  My experience seems to 
indicate VNC being faster on a LAN.  Since the console is being redirected 
in the host, rather than the guest, it seems to demand less processing 
power.  Also, turning off remote access in the guest loads less software. 
Since the host supports the VNC console access, it becomes available much 
sooner than WinXP get termserv up.
>>  Please share any anecdotal information regarding user reactions and/or
>>implementation issues.
>
> There's nothing cooler than Xen, but IMHO opinion I would be using 
> something
> a bit more stable for Windows guests, it's not the right tool for
>this<
> job
> as far as I am concerned.
>
> YMMV
  I've got some local databases with chatty Windows clients that becomes 
unuseable across the WAN and doesn't play well with MS Terminal Services. 
Rather than have a stack of physical WinXP machines for my remote users, I'm
looking at virtualization.  VMWare gets too expensive, too fast.

From: "Julian Price", Wednesday, April 22, 2009 3:46 PM
> I use RDP because it allows copy & paste of text between the local and
> remote machines.  VNC does not, unless I've just not got it set up
right.
>
> - Julian
  Most of my users are not sophisticated enough to handle mixing remote and 
local modes.  I'm expecting to turn the remote machine into a thin client 
equivalent (enabling me to move the WinXP license to the VM).

  This seems to reduce some of my potential support issues.

  I'm currently experimenting with Thinstation (thinstation.net).  There are
a couple of issues with it, like sound, but I'm leaving those issues for 
later.

Julian Price wrote on Wed, 22 Apr 2009 22:46:44 +0100:
> I use RDP because it allows copy & paste of text between the local and 
> remote machines.  VNC does not, unless I've just not got it set up
right.
I have always been doing that (copy text to VNC). I run VNC for my Windows 
*hosts* rather than RDP because I can attach to an existing console session 
and not logout the console. RDP doesn't attach to a session but opens a new 
one.

Kai

-- 
Kai Sch?tzl, Berlin, Germany
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