Date: Sat, 15 Feb 2014 11:52:55 -0500 From: Mason Loring Bliss <mason@blisses.org> To: Warren Block <wblock@wonkity.com> Cc: Polytropon <freebsd@edvax.de>, freebsd-questions@freebsd.org Subject: Re: Installing without blowing away GRUB/MBR Message-ID: <20140215165255.GE4472@blisses.org> In-Reply-To: <alpine.BSF.2.00.1402150909390.95587@wonkity.com> References: <20140215025211.GC4472@blisses.org> <20140215100854.5f429b0c.freebsd@edvax.de> <alpine.BSF.2.00.1402150909390.95587@wonkity.com>
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On Sat, Feb 15, 2014 at 09:18:45AM -0700, Warren Block wrote: > That article probably does not apply to this situation (or maybe any... I > added a warning to it last week). A ZFS mirror is probably a better > solution than ZFS on top of a gmirror. Yeah, that's the plan. > Looking back on this thread, I'm confused. The subject says MBR, but then > the text talks about GPT. If possible, avoid MBR and the "partitions inside > a partition" mess of EBR or MBR slice/FreeBSD partitions and just use GPT. Very specifically, here's what I've got. The box in question already dual-boots Debian and Windows on various disks. Two of the disks are already GPT and already have Debian Wheezy in various partitions, with GRUB installed to boot everything. I've got free space at the end of each, and I want to install FreeBSD there, with most of the space being in a ZFS mirror, with each half sitting on GELI. I don't want to blow away the existing GRUB - I want to use it to boot FreeBSD as well as the other systems currently there. My current belief is that I can install a stage1/stage2 into a freebsd-boot partition of some very small size, and that that will be able to use a stage3 off of the ZFS mirror. I also believe that I don't need stage0, as GRUB will be doing that. I'm not sure about these things. The other point of uncertainty is if the FreeBSD 10 installer will accomodate this automatically, just asking me if I want to touch the MBR or not. This is, for instance, something the Debian installer does. So, here's one of the disks as it stands: Number Start End Size File system Name Flags 1 1049kB 2097kB 1049kB bios_grub 2 2097kB 130MB 128MB raid 3 130MB 450GB 450GB raid There's a third disk that has Windows and some utility space on it. There's space at the end of the first two that I want to use for FreeBSD, so I'd theoretically be looking at this mocked-up result: Number Start End Size File system Name Flags 1 1049kB 2097kB 1049kB bios_grub 2 2097kB 130MB 128MB raid 3 130MB 450GB 450GB raid 4 450GB 450GB 1MB freebsd-boot 5 450GB 480GB 30GB geli GRUB in the MBR would pick up an entry for FreeBSD and presumably chainload the stage1/stage2 from partition 4, unless it can deal with the ZFS mirror sitting on GELI directly, which would shock me. Currently the Linux portions form a RAID 1, LUKS sits on that, LVM sits on that... The FreeBSD side will have GELI at the bottom since ZFS incorporates the mirroring and volume management functionality, really everything but the encryption itself. (I'd love it if it did the encryption too. =shakes fist at Oracle=) I don't know if the freebsd-boot would go on a gmirror or if I'd just tell things that update it to touch both disks. With GRUB, I do the latter - update-grub writes to both disks. My understanding is that this is pretty much what I'd get out of the installer if I said I wanted encrypted, mirrored ZFS - the only difference is that I want to preserve the existing GRUB. I'm taking off for a car appointment soon, and depending on what I read once I get back I'll either try the install directly on hardware, or simulate it in a VM first. I'd rather save the time and go straight to hardware if what I want to do doesn't look too thorny. -- Mason Loring Bliss (( "In the drowsy dark cave of the mind dreams mason@blisses.org )) build their nest with fragments dropped http://blisses.org/ (( from day's caravan." - Rabindranath Tagore
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