[vox] Want to make some money?

[Bill Broadley]

After such a pro-citrix/Xen post I figured I'd post my (admittedly 
vague) recollection of the Xen history.

I was an early supporter of Xen.  I started a couple servers on campus 
and off and was pretty pleased with the result.  Xen related 
talks/discussions resulted in numerous other departments/organizations 
using Xen.  At the time it was very straight forward to get the source 
and patches required for Xen to run on a current linux distro.  Install 
directions often included a turn key script for downloads of Xen source.

Then it got harder to find/download, you had to fill out a form, create 
an account, etc.

They the supply completely stopped, no new kernel patches/source were 
released.

At this time I had 6 or so Dom0/hosts, and wanted to roll out a new 16 
disk Dom0 and wanted a semi-recent kernel so I could get raid-scrubbing. 
  This was before Redhat back ported RAID scrubbing which at the time 
required something newer than 2.6.20.

Some grad student in Italy was doing some research into virtualization. 
  He contributed some patches where were picked up by someone who tried 
to get them to apply to fedora's kernel.  Suse worked from them for 
awhile, as did ubuntu.  Forums were filled with issues related to them, 
death under heavy network loads, problems with larger disk arrays, 
various ugly side effects were pretty well known.  Xen also had numerous 
ugly warts at the time, stealing the serial driver
for use with consoles was a particularly painful one for me.  I had to 
try dozens of kernels to find one that worked with my network, raid 
controller, and kernel.

At that point I think it had been over a year since a single line of 
kernel code came out of Xen.  Various virtualization products were 
lobbying for mainline kernel changes.  Said community said propose 
changes that will mean all of your needs and they will be considered. 
My memory is KVM played nice and got changes submitted, Xen did not and 
complained rather loudly.

After *ANOTHER* year of no new patches/kernels from Xen all 3 big linux 
companies (Redhat, Ubuntu, and SUSE) decide to abandon Xen in favor of 
KVM.  Oracle decided to stick with Xen but I'll let Oracle's record with 
open source speak for itself.  Thank god for the ability to fork open 
source projects.

The good news is that Xen now seems to be playing nicely with the 
kernel, contributing patches, and generally working better with the 
linux community.  I was pretty shocked it took 3 of the biggest linux 
companies's defections to trigger it.

So while Citrix has been financially successful and at least for awhile 
they seemed to be focusing all their efforts on integration and 
marketing and none on their core technologies.  Sure that's good for 
stock prices in the short term, but seems like a poor long term plan. 
Granted they had an early lead in virtualization, which from a technical 
perspective (IMO) they lost.

It will be interesting to see what Amazon (which runs on RHEL + Xen 
today) and various cloud providers (often using KVM) do over the next 
year.  Especially with RHEL 6 not supporting Xen and Amazon offering 
Oracle's virtualization (in addition to Xen).

More recently in 3 different organizations that used to run Xen now run 
KVM.  Installation is a dream (click virtualization during the install) 
and I'm a big fan of libvirt and DRBD used with KVM.

Disclaimer:  I don't own stock or have any financial relation with any 
of the above mentioned companies.