[NTLUG:Discuss] If not VMWare 2.x or UML...then what?

[Fred Hensley]

For client production environments (bank data centers, corporate office
headquarters, etc) I've had some great success and reliability deploying
the latest Citrix Xenserver v5.5.

BTW, this is *not* the opensource version of Xen, but the commercial
package downloaded directly from Citrix.

Some of the good points are:

1.  Full production-ready environment with terrific stability.  My Xen
server uptimes for the server and most vm's are well over 16 months
since installation.  Upgrades have been smooth since V4.1, and
relatively painless.

2.  Citrix made a bold move to increase marketshare by releasing free
licenses for their former "full" enterprise version, including:
live-migration of vm's between servers, resource pools (both servers and
storage), etc.  Some of the few remaining high availability features are
only available by annual subscription, but I haven't needed them yet for
my clients.

3.  Xen was the first to launch a bare-metal implementation of the
server stack, dramatically increasing performance over early iterations
of VMware, and likely resulting in the competitive ESX version release
by VMWare.

4.  A new-and-improved local text-based management console is much
preferred to the earlier linux command line prompt, permitting even my
hyper-linux-command-line adverse clients the ability to do basic
management functions onsite.

5. Good support for the OS from Redmond.  Just installed a couple copies
of Windows 2008 server per customer requirement without a hitch.  Once a
Windows vm is installed, I run a separate Xen program which optimizes
various drivers for the virtualized environment, thus speeding up
response and performance quite well.  But wherever possible, we take
full advantage of the available linux VM templates available to install
the latest linux distributions (e.g. Debian, RHEL, SLES, Ubuntu, Centos,
etc.).

6.  The Xenserver documentation and full CD ISO's are plentiful, well
maintained, and completely free for download after a free registration
at Citrix.com.  Post installation a license file must be self-generated
online via citrix.com and entered for each deployed server within 30 days.

Some of the gotcha's might be:

1.  Server hardware requires 64 bit processors.  Pay close attention to
the published hardware compatibility lists.

2.  The latest server management tool (called Xencenter) is written as a
.NET application, and consequently requires a Windows client to run.  I
have overcome this annoyance by installing (1) Windows XP vm at each
deployed client site to remotely manage the site servers.

3.  Beware the hardware availability lists, especially concerning RAID.
   Software RAID has been a real problem to implement with Xen, so the
safest alternative for me has been installing a 3Ware HW raid card with
each production server.

4.  PCI/USB pass-through to VM's is still not supported, with the
exception of NIC cards.  So if you have a vendor-specific USB dongle or
 plug-in PCI/PCIE card for use by your guest VM, you're outta luck for now.


Several meetings ago Chris Cox pointed out the likelihood of KVM
eventually supplanting both Xen and VMWARE.  That may ultimately happen,
but for now IMHO there is much work to be done before they achieve
production-ready stability.

Also, Ralph did a great NTLUG presentation on other VM environments
which may be helpful to review.

Overall, I've been very pleased with commercial Xenserver for production
environments, and will continue deploying them wherever needed.  Is it
perfect?  Nope.  But, if this meets your requirements, and assuming your
hardware is compatible, it is relatively easy and painless to
experiment, test, and deploy for free.

A couple of Citrix and fan-boy links which may (or may not) help:

http://www.citrix.com/English/NE/news/news.asp?newsID=1854962
http://www.virtualization.info/2009/02/citrix-xenserver-is-now-free-xencenter.html

As always, ymmv...

Best,

-Fred-

Fred Hensley



Richard wrote:
> Well, I've about had it with VMWare Server 2.x.  The stability is not 
> there, the bugs are too numerous and managing the blasted thing via an 
> http browser is painfully slow.
> 
> UML is great for virtualizing linux, but what if one wanted to 
> virtualize a Redmond OS?
> 
> 
> So, what are viable options that one can put into production?   What are 
> the benefits, limitations, gotchas?
> 
> I need to find something else.  I'm not liking where VMWare is going.
>