From owner-freebsd-stable@FreeBSD.ORG Thu Mar 29 19:44:03 2007 Return-Path: X-Original-To: freebsd-stable@freebsd.org Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id A071716A407 for ; Thu, 29 Mar 2007 19:44:03 +0000 (UTC) (envelope-from dillon@apollo.backplane.com) Received: from apollo.backplane.com (apollo.backplane.com [216.240.41.2]) by mx1.freebsd.org (Postfix) with ESMTP id 8828613C44B for ; Thu, 29 Mar 2007 19:44:03 +0000 (UTC) (envelope-from dillon@apollo.backplane.com) Received: from apollo.backplane.com (localhost [127.0.0.1]) by apollo.backplane.com (8.13.8/8.13.7) with ESMTP id l2TJhwNR094666; Thu, 29 Mar 2007 12:43:58 -0700 (PDT) Received: (from dillon@localhost) by apollo.backplane.com (8.13.8/8.13.4/Submit) id l2TJhwR9094665; Thu, 29 Mar 2007 12:43:58 -0700 (PDT) Date: Thu, 29 Mar 2007 12:43:58 -0700 (PDT) From: Matthew Dillon Message-Id: <200703291943.l2TJhwR9094665@apollo.backplane.com> To: Ivan Voras References: <395450.751174710071770.JavaMail.root@ly.sdf.com> <200703291722.l2THM225092894@apollo.backplane.com> <460BF922.4050604@fer.hr> Cc: freebsd-stable@freebsd.org Subject: Re: Xen Dom0, are we making progress? X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 29 Mar 2007 19:44:03 -0000 :Virtual kernels are a cool idea, but I (and I believe practically anyone :using FreeBSD for non-development work) would much rather see a Xen-like :functionality (to be precise: ability to run foreign kernels and :Windows; qemu is too slow) than just a variation of the native kernel. There is certainly a functionality there that people will find useful, but you also have to realize that Xen involves two or more distinct operating systems which will multiply the number of bugs you have to deal with and create major compatibility issues with the underlying hardware, making it less then reliable. Really only the disk and network I/O can be made reliably compatible in a Xen installation. Making sound cards, video capture cards, encryption cards, graphics engines, and many other hardware features work well with the guest operating system will not only be difficult, but it will also be virtually unmaintainable in that environment over the long term. Good luck getting anything more then basic application functionality out of it. For example, you would have no problem running pure network applications such as web and mail servers on the guest operating system, but the moment you delve outside of that box and into sound and high quality (or high performance) video, things won't be so rosy. I don't see much of an advantage in having multi-OS hardware virtualization for any serious deployment. It would be interesting and useful on a personal desktop, at least within the scope of the limited hardware compatibility, but at the same time it will also lock you into software and OS combinations that aren't likely to extend into the future, and which will be a complete an utter nightmare to maintain. Any failure at all could lead to a completely unrecoverable system. -Matt Matthew Dillon