Xen dom0 patches are available for 2.6.27, 2.6.29, 2.6.31, 2.6.32, 2.6.33 etc..most people prefer 2.6.32 atm, since that's the long-term maintained kernel from both kernel.org and xen.org. For more information: http://wiki.xensource.com/xenwiki/XenDom0Kernels . Xen developers are also busy preparing (and rewriting) the Xen dom0 support for the mainline Linux Xen pvops framework, which has been in upstream Linux since 2.6.24.

RHEL5 will fully support Xen until 2014 (which is when RHEL5 goes EOL). Redhat has stated this multiple times. Also upcoming RHEL6 runs as Xen guest, on RHEL5 Xen host/dom0. So there's no need to switch away from Xen.

From the new enterprise distributions Suse Linux Enterprise 11 (SLES11) SP1 fully supports Xen, including the new Xen 4.0 hypervisor, and Linux 2.6.32 based dom0 kernel. OpenSUSE also has Xen included/supported. Upcoming Debian 6.0 ("Squeeze") will also have Xen (including dom0).

This has changed pretty much lately. A lot of new documentation has been written to the wiki, for example: http://wiki.xensource.com/xenwiki/XenCommonProblems has a lot of stuff and links to other new documentation pages. Have you heard of XCP (Xen Cloud Platform, http://www.xen.org/products/cloudxen.html)? It's a full "Xen distribution" featuring install CD, including everything needed for multi-host/pool management. No need to install custom kernels or anything. You can use OpenXenCenter (http://www.openxencenter.com/) to manage it, if you need a GUI tool.

RHEL6 will support running as Xen guest, both PV and HVM. You can use RHEL5 as the Xen host (dom0), and run RHEL6 guests on it.

Did you try XCP (Xen Cloud Platform, http://www.xen.org/products/cloudxen.html) ? XCP 0.5 is coming out in June.. you can manage it using OpenXenCenter (http://www.openxencenter.com). Basicly XCP is XenServer opensourced and developer further..

I think that has been already supported for a while in Xen..

Fedora 13 contains Xen hypervisor and tools, but it doesn't contain rpm package for a Xen dom0 capable kernel. There are unofficial Fedora rpm packages for a Xen dom0 capable kernel, based on the upstream pvops dom0 kernels (Linux 2.6.32). More information about Fedora Xen status and links to rpms see: http://fedoraproject.org/wiki/Features/XenPvopsDom0 . More information about available Xen dom0 kernel options see: http://wiki.xensource.com/xenwiki/XenDom0Kernels .

Some comments.. Xen hypervisor (xen.gz) is not meant to be integrated to Linux kernel. Xen is designed to be a separate piece of software. Xen is a secure, type-1 baremetal hypervisor, not a module for Linux. Xen dom0 ("service console") can be Linux, NetBSD or OpenSolaris. Most people use Linux as Xen dom0. When Linux is used as dom0 it needs to be able to run as Xen dom0 (obviously) - and this is where some people have had pain. For a long time the official Xen dom0 kernel patches were only available for Linux 2.6.18. This was difficult for many people and caused some distros to drop Xen dom0 kernel support because they couldn't affort porting the patches to newer kernels themselves. Today the situation is different. Xen developers are actively working on rewriting the Xen dom0 patches based on the (already existing) upstream pvops framework. pvops has been in the upstream Linux kernel since 2.6.24. Xen pvops dom0 patches are available today for the long-term maintained 2.6.32 kernel, and also for 2.6.31, 2.6.33 and 2.6.34. Novell has also forward-ported the old/traditional Xenlinux patches from 2.6.18 to first 2.6.27 and also to 2.6.31, 2.6.32 and 2.6.33. So there are many options today. For more information about the various Xen dom0 kernels see: http://wiki.xensource.com/xenwiki/XenDom0Kernels Also xen.org offers XCP (Xen Cloud Platform) which is a full platform, including installation CD and multi-host/pool management. If you use XCP you don't need to install custom kernels or anything - you get all included in the XCP bundle. More information about XCP: http://www.xen.org/products/cloudxen.html

Actually Xen has some form of memory overcommit nowadays.. check tmem patches from Oracle. I think they'll be part of upcoming Xen 4.0 release.

It's funny.. that spreadfirefox.com has a "DOWNLOAD FIREFOX 3" link: http://www.mozilla.com/en-US/firefox?p=downloadday Which only gives firefox 2.0.0.14 download links.. Seems they have some problems.. doesn't help with the world record stuff..