Two comments on the recent back and forth on hypervisor performance. Both bloggers use VMware Infrastructure in their jobs every day, just so you know their biases going in.

Geert Baeke:

The results are interesting because performance is very similar. But
is this enough to conclude that the XenSource product is a valid alternative to the VI3 offering? We think not and this for several

  1. It is important for our customers to use a
    product that has established itself in the market. The XenSource
    product is not there yet and will need some time to mature.
  2. The
    management tools have to be top-notch. Our experience shows that most
    customers virtualize Windows systems and are primarily running Windows
    in their environment. They do not want to mess with Linux configuration
    and management so it is important that the management products allow
    this. VI Client with VI3 comes very close to this need although some
    actions do require some command line knowledge.
  3. Hardware
    compatibility and support. ESX 3.0.1 supports a wide array of hardware
    and storage devices. Installation and configuration is very
    straightforward. XenSource’s products are not at that level yet.

(Note Geert is now trying out XenEnterprise (part 1, part 2) to compare for himself.)

Kent A aka Bowulf:

The trick is not virtualization of a system or even virtualization
at near native performance — no matter how difficult current Microsoft
products make it look. There are or will be many products that will do
this in due time. If all you want is lowest cost of obtaining
virtualization and only have 10-15 servers, perhaps that is all that
matters. However, there are a number of other “must haves” — such as
VMotion. If I have to take a physical host down — do I really want to
affect 20-30 VMs as well. As Geert Baeke correctly points out, the
management capabilities in Virtual Center far outstrip the other
competitors shipping products. Enterprise data centers need that level
of granularity of control and capabilities — in fact they often need
more as evidenced by the throngs of companies buying 3rd party add-ons
like ESX Charter and P2V applications, like Leostream.

Where is the 3rd party industry surrounding Xen products at this
point? I am not saying this to discount the Xensource product only to
highlight the differences. Scalability of solutions is just one area
that this lack of features shows. (Although VMware’s products also face scalability on the extreme end as well– >100 ESX hosts & 1500 VMs) Where are the Data Centers using 1500 VMs running upon Xen outside the hosting world?