Date: Tue, 7 Aug 2018 20:57:10 +0200 From: Jakub Chromy <hicks@cgi.cz> To: freebsd-virtualization@freebsd.org Subject: Re: Seeking advice on virtualization Message-ID: <a88a341c-fb3b-453e-7151-9e992f35586a@cgi.cz> In-Reply-To: <20180807170648.GA1599@tau1.ceti.pl> References: <20180805224205.GB17784@tau1.ceti.pl> <CADdqeiM8rNGGgw7vyUT%2BCGxmcct93NK9xHCFGf4g2B6dG_xhrA@mail.gmail.com> <20180807170648.GA1599@tau1.ceti.pl>
next in thread | previous in thread | raw e-mail | index | archive | help
> 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. ZFS ZVOL is a true "raw device" as well... (or at least it did behave like that for me): dd if=/dev/zvol/pool/mypornhubpremiumarchive0 of=/var/vm/mypornhubpremiumarchive0.raw but you get snapshots, zfs send | zfs recv and stuff. -- regards / s pozdravem Jakub Chromy CGI Systems div. ---------------- CGI CZ s.r.o. sales@cgi.cz 775 144 257 234 697 102 www.cgi.cz On 7.8.2018 19:06, Tomasz Rola wrote: > 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). >
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?a88a341c-fb3b-453e-7151-9e992f35586a>