Ruslan Sivak russ@vshift.com writes:
running vmware under a xenU guest wouldn't lift any ram limit imposed by the xen kernel or dom0.
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The 4GB limit is artificial, and only applies to the vm's started using their closed source XenSource. The host OS is most likely CentOS 5, and sees the whole 8GB (although it's not x64, so I'm guessing they use PAE or something.)
It is PAE.
I only need 8GB of ram support, and no other features that are offered in XenStandard, so it seems kind of a waste to pay $1k per server for that. If another virtualization technology was installed on that OS, you can get the use of the other 4GB, and if not, I can always run my apps on Dom0, although I'd prefer to not install too much stuff on Dom0.
First, The Dom0 OS runs as a guest of the Xen hypervisor- it is just a guest that happens to have access to the PCI bus as well. The Xen hypervisor still controls what ram and CPU all domains including the Dom0, can see; if the xen kernel is limiting you to 4G ram total, that limit will apply in the Dom0 as well.
Also, you are not going to be able to run a virtualization technology that uses the hardware virtualization support from within a Xen guest, even if that Xen guest happens to be the Dom0. The Xen hypervisor controls access to those instructions.
You can run virtualization technologies that don't require HVM- OpenVZ and linux vserver will both work fine. Heck, you can do that within an unprivileged Xen DomU, but that won't help you if you want to run windows.