From owner-freebsd-virtualization@freebsd.org Tue Aug 7 17:07:05 2018 Return-Path: Delivered-To: freebsd-virtualization@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id CC79A1064B86 for ; Tue, 7 Aug 2018 17:07:05 +0000 (UTC) (envelope-from rtomek@tau1.ceti.pl) Received: from mailout4.ceti.pl (mailout4.ceti.pl [62.121.128.44]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 6A9B877E0C for ; Tue, 7 Aug 2018 17:07:05 +0000 (UTC) (envelope-from rtomek@tau1.ceti.pl) Received: from localhost (localhost [127.0.0.1]) by mailout4.ceti.pl (Postfix) with ESMTP id 64C8FC0552F15; Tue, 7 Aug 2018 19:06:57 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at mailout1.ceti.pl Received: from mailout4.ceti.pl ([62.121.128.44]) by localhost (mailout1.ceti.pl [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id eDGTm34IKo12; Tue, 7 Aug 2018 19:06:48 +0200 (CEST) Received: from tau1.ceti.pl (tau.ceti.pl [62.121.128.11]) by mailout4.ceti.pl (Postfix) with ESMTP id A26DAC0552E29; Tue, 7 Aug 2018 19:06:48 +0200 (CEST) Received: by tau1.ceti.pl (Postfix, from userid 3727) id 6E0B2960E07; Tue, 7 Aug 2018 19:06:48 +0200 (CEST) Date: Tue, 7 Aug 2018 19:06:48 +0200 From: Tomasz Rola To: Paul Webster Cc: FreeBSD virtualization , Tomasz Rola Subject: Re: Seeking advice on virtualization Message-ID: <20180807170648.GA1599@tau1.ceti.pl> References: <20180805224205.GB17784@tau1.ceti.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-BeenThere: freebsd-virtualization@freebsd.org X-Mailman-Version: 2.1.27 Precedence: list List-Id: "Discussion of various virtualization techniques FreeBSD supports." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 07 Aug 2018 17:07:06 -0000 On Mon, Aug 06, 2018 at 12:07:13AM +0100, Paul Webster wrote: > In theory as ZFS works on both linux and BSD you could simply use vdevs and > snapshots for easy transport Um-hm. I was writing about "hard disk file" format, in which a hypervisor (i.e. bhyve, kvm, virtualbox) is keeping a disk for emulated machine. Wikipedia calls it "img format": https://en.wikipedia.org/wiki/IMG_(file_format) Advantage from using this format (as opposed to something like qcow or vmhd) is that, in theory (and even in practice) one can boot such machine (I mean, virtual machine defined with such "raw" hard drives) using any hypervisor. Or to put it differently, it is not proprietary and is the easiest one to implement, so it is what most probably will keep being used years or decades from now (in whatever hypervisor / PC emulator of the future day is fashionable). I believe in the past I have installed an OS (say, FreeDOS) using virtualbox and after deciding I would not use virtualbox in a future, I started to boot said machine using kvm. Likewise, I believe some OSes rejected being installed under certain hypervisor, so one had to install them using this other hypervisor and then could happily continue to run it under his preferred hypervisor. All of this made possible thanks to avoiding file formats supported by one or only few hypervisors. Of course there are many hd-file formats and some are supported by more than one hypervisor, but the easiest one is raw and in case of emergency it can be also mounted as any other block device (always, I guess, but I would pay attention to block size mismatch). -- Regards, Tomasz Rola -- ** A C programmer asked whether computer had Buddha's nature. ** ** As the answer, master did "rm -rif" on the programmer's home ** ** directory. And then the C programmer became enlightened... ** ** ** ** Tomasz Rola mailto:tomasz_rola@bigfoot.com **