ESXi 4 and XenServer 5.5 deployment differences

[meetom]

First of all, I like to state that I'm very new to virtualization. I've been trying to weigh the differences between ESXi and XenServer 5.5. I like to see if someone out there can help clear up some questions I have.

With XenServer, I believe by default the guest runs in HVM mode unless you install via the templates. A Xenified kernel is installed if you use the template and runs in PV(paravirtualization) mode.

My questions:

Does ESXi have something similar to Xenserver in respect to having a modifed kernel in order to run in PV mode? If so then what is the default VM mode if I don't run a modified kernel?

Does HVM apply to ESXi?

Thanks in advance

[microkid]

ESX uses hardware virtualization, no paravirtualization like XenServer. When you create a VM in XenServer, it runs in HVM mode until you install the XenTools, which will install and replace some drivers to the VM can run in paravirtualized mode. This is why (according to numerous tests) VM's in XenServer are a bit faster than in ESX. A VM in ESX is always running in HVM mode. By installing the Vmware Tools, a set of optimized drivers are installed so the VM can access the virtualized nic's, disk, storage adapters etc.

[meetom]

This clears it up. Thank You!