Date: Tue, 7 Aug 2018 20:20:58 +0100 From: Paul Webster <paul.g.webster@googlemail.com> To: Jakub Chromy <hicks@cgi.cz> Cc: "freebsd-virtua." <freebsd-virtualization@freebsd.org> Subject: Re: Seeking advice on virtualization Message-ID: <CADdqeiOeFn1F8cqWuVnskiU4Xa720HLJQcaN-CJ8Qbkrp%2BH2Tw@mail.gmail.com> In-Reply-To: <a88a341c-fb3b-453e-7151-9e992f35586a@cgi.cz> References: <20180805224205.GB17784@tau1.ceti.pl> <CADdqeiM8rNGGgw7vyUT%2BCGxmcct93NK9xHCFGf4g2B6dG_xhrA@mail.gmail.com> <20180807170648.GA1599@tau1.ceti.pl> <a88a341c-fb3b-453e-7151-9e992f35586a@cgi.cz>
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even cooler you get 'clones' so you can say make a raw/zvol of debian or whatever you like then if you make a snapshot of it and clone it to something else 'debian2' it uses no space until you write/delete/edit something, basically the clone only has diffs. And yes zvols are literally like raw devices, dd style you can infact take a raw image and dd it to a zvol On 7 August 2018 at 19:57, Jakub Chromy <hicks@cgi.cz> wrote: > 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). >> >> > _______________________________________________ > freebsd-virtualization@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-virtualization > To unsubscribe, send any mail to "freebsd-virtualization-unsubs > cribe@freebsd.org" >
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