Date: Thu, 1 Sep 2022 17:51:59 -0700 From: Dan Mahoney <freebsd@gushi.org> To: paul beard <paulbeard@gmail.com> Cc: FreeBSD-questions <freebsd-questions@freebsd.org> Subject: Re: making a disk/slice bootable Message-ID: <03F3F917-CCF5-44BB-85F0-00AD3ADF9818@gushi.org> In-Reply-To: <CAMtcK2qd%2BKstLC1oKZm9OPaOYh=gSHxYV=ZjCud2AF5G4n=-Aw@mail.gmail.com> References: <CAMtcK2r4L3SCba4EZt73=F2=fnBnEPGvEL3GCM_38R8_e5meXg@mail.gmail.com> <07BE254D-7701-47F2-94E3-09ED7229FB2B@gushi.org> <A99C0412-FD34-46D6-AB9A-AFC45FB10C10@gushi.org> <CAMtcK2qd%2BKstLC1oKZm9OPaOYh=gSHxYV=ZjCud2AF5G4n=-Aw@mail.gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
--Apple-Mail=_BD5E5957-31BB-487E-9ED5-3230E0CA0007 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 I haven't used recoverdisk. If you're going to mirror, use one of the = other things I mentioned. gmirror is low-impact and easy enough to use = and supported by the various boot loaders. If you're just cloning disk to similar disk with rsync, you should not = need to do this more than once, unless maybe if you upgrade your system. = Normal freebsd-update upgrades do not generally touch the boot blocks. = The best advice I can give is "test this BEFORE you need it". Rip your = primary drive out and see if you still boot. For a lightweight system, even zfs mirroring is okay, but it does use = some ram for caching and the like, so I wouldn't try it with a tiny = embedded box. -Dan > On Sep 1, 2022, at 17:47, paul beard <paulbeard@gmail.com> wrote: >=20 > yeah, I was pretty sure I was using the wrong tool=E2=80=A6thanks for = this.=20 >=20 > So a further Q=E2=80=A6if I continue to use recoverdisk from ports to = mirror my boot disk to a copy, is it best practice to do this on the = mirror after the mirroring is completed? For all I know there is a far = better way to do that but this is a FreeBSD 11 system (!) that has just = been doing its thing for some years. So it worked (more or less) when it = was set up. A backup you can't use isn't much use, as I have learned = (again, I expect).=20 >=20 > On Thu, Sep 1, 2022 at 5:20 PM Dan Mahoney <freebsd@gushi.org = <mailto:freebsd@gushi.org>> wrote: > > > > Fdisk is for old-school partitions (where disks had only 1-4 primary = partitions, and then subdivided those partitions into "slices" = (bsdlabel). > > > > I'm pretty sure the command you're looking for is: > > > > gpart bootcode -b /boot/pmbr -p /boot/gptboot -i 1 ada1 > > > > In english, this says: > > > > * Stick the "protective master boot record" on the root of the disk = (/boot/pmbr) > > * Write a partition boot label from the file specified... > > * to this indexed partition (-i 1) > > * ...on ada1 > > > > =46rom there, you may need to tell the stage 0 loader where to find = your next bootable partition on the next boot() prompt. > > > > -Dan > > > > > > > On Sep 1, 2022, at 16:44, Dan Mahoney <freebsd@gushi.org = <mailto:freebsd@gushi.org>> wrote: > > > > > > > > > > > >> On Sep 1, 2022, at 16:41, paul beard <paulbeard@gmail.com = <mailto:paulbeard@gmail.com>> wrote: > > >> > > >> I have been mirroring the virtual disk in a FreeBSD vm for a = couple of years and the main disk got corrupted. The mirrored disk = doesn't boot, says it can't find a kernel, so I think I missed out on an = additional step, writing an MBR or boot sector, perhaps. > > >> > > >> The files are all there if I mount them from a VM with FreeBSD.I = assume there is a way to make a mountable disk bootable. fdisk and = gpart are available but it's been a long time since I messed around with = those. > > > > > > Let's start with the obvious: Can you post your disk layout? = Mirrored how? Gmirror/ZFS/Hardware raid/etc? MBR or Gpart? > > > > > > What commands have you tried thusfar? > > > > > > What does the boot so far look like (i.e. are you hitting the = stage 0 boot loader, and getting the loader prompt?) > > > > > > More info required, please, but this sounds very fixable. > > > > > > -Dan > > >=20 >=20 > -- > Paul Beard / www.paulbeard.org/ <http://www.paulbeard.org/>; --Apple-Mail=_BD5E5957-31BB-487E-9ED5-3230E0CA0007 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8 <html><head><meta http-equiv=3D"Content-Type" content=3D"text/html; = charset=3Dutf-8"></head><body style=3D"word-wrap: break-word; = -webkit-nbsp-mode: space; line-break: after-white-space;" class=3D"">I = haven't used recoverdisk. If you're going to mirror, use one of = the other things I mentioned. gmirror is low-impact and easy = enough to use and supported by the various boot loaders.<div = class=3D""><br class=3D""></div><div class=3D"">If you're just cloning = disk to similar disk with rsync, you should not need to do this more = than once, unless maybe if you upgrade your system. Normal = freebsd-update upgrades do not generally touch the boot blocks. = The best advice I can give is "test this BEFORE you need it". = Rip your primary drive out and see if you still boot.<br = class=3D""><div class=3D""><br class=3D""></div><div class=3D"">For a = lightweight system, even zfs mirroring is okay, but it does use some ram = for caching and the like, so I wouldn't try it with a tiny embedded = box.<br class=3D""><div><br class=3D""></div><div>-Dan</div><div><br = class=3D""><blockquote type=3D"cite" class=3D""><div class=3D"">On Sep = 1, 2022, at 17:47, paul beard <<a href=3D"mailto:paulbeard@gmail.com" = class=3D"">paulbeard@gmail.com</a>> wrote:</div><br = class=3D"Apple-interchange-newline"><div class=3D""><div dir=3D"ltr" = class=3D"">yeah, I was pretty sure I was using the wrong tool=E2=80=A6than= ks for this. <br class=3D""><br class=3D"">So a further Q=E2=80=A6if I = continue to use recoverdisk from ports to mirror my boot disk to a copy, = is it best practice to do this on the mirror after the mirroring is = completed? For all I know there is a far better way to do that but this = is a FreeBSD 11 system (!) that has just been doing its thing for some = years. So it worked (more or less) when it was set up. A backup you = can't use isn't much use, as I have learned (again, I expect). <br = class=3D""><br class=3D"">On Thu, Sep 1, 2022 at 5:20 PM Dan Mahoney = <<a href=3D"mailto:freebsd@gushi.org" = class=3D"">freebsd@gushi.org</a>> wrote:<br class=3D"">><br = class=3D"">> Fdisk is for old-school partitions (where disks had only = 1-4 primary partitions, and then subdivided those partitions into = "slices" (bsdlabel).<br class=3D"">><br class=3D"">> I'm pretty = sure the command you're looking for is:<br class=3D"">><br = class=3D"">> gpart bootcode -b /boot/pmbr -p /boot/gptboot -i 1 = ada1<br class=3D"">><br class=3D"">> In english, this says:<br = class=3D"">><br class=3D"">> * Stick the "protective master boot = record" on the root of the disk (/boot/pmbr)<br class=3D"">> * Write = a partition boot label from the file specified...<br class=3D"">> * = to this indexed partition (-i 1)<br class=3D"">> * ...on ada1<br = class=3D"">><br class=3D"">> =46rom there, you may need to tell = the stage 0 loader where to find your next bootable partition on the = next boot() prompt.<br class=3D"">><br class=3D"">> -Dan<br = class=3D"">><br class=3D"">><br class=3D"">> > On Sep 1, = 2022, at 16:44, Dan Mahoney <<a href=3D"mailto:freebsd@gushi.org" = class=3D"">freebsd@gushi.org</a>> wrote:<br class=3D"">> ><br = class=3D"">> ><br class=3D"">> ><br class=3D"">> >> = On Sep 1, 2022, at 16:41, paul beard <<a = href=3D"mailto:paulbeard@gmail.com" class=3D"">paulbeard@gmail.com</a>>= wrote:<br class=3D"">> >><br class=3D"">> >> I have = been mirroring the virtual disk in a FreeBSD vm for a couple of years = and the main disk got corrupted. The mirrored disk doesn't boot, says it = can't find a kernel, so I think I missed out on an additional step, = writing an MBR or boot sector, perhaps.<br class=3D"">> >><br = class=3D"">> >> The files are all there if I mount them from a = VM with FreeBSD.I assume there is a way to make a mountable disk = bootable. fdisk and gpart are available but it's been a long time = since I messed around with those.<br class=3D"">> ><br = class=3D"">> > Let's start with the obvious: Can you post your = disk layout? Mirrored how? Gmirror/ZFS/Hardware = raid/etc? MBR or Gpart?<br class=3D"">> ><br class=3D"">> = > What commands have you tried thusfar?<br class=3D"">> ><br = class=3D"">> > What does the boot so far look like (i.e. are you = hitting the stage 0 boot loader, and getting the loader prompt?)<br = class=3D"">> ><br class=3D"">> > More info required, please, = but this sounds very fixable.<br class=3D"">> ><br class=3D"">> = > -Dan<br class=3D"">><br class=3D""><br class=3D""><br = class=3D"">--<br class=3D"">Paul Beard / <a = href=3D"http://www.paulbeard.org/" class=3D"">www.paulbeard.org/</a></div>= </div></blockquote></div><br class=3D""></div></div></body></html>= --Apple-Mail=_BD5E5957-31BB-487E-9ED5-3230E0CA0007--
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?03F3F917-CCF5-44BB-85F0-00AD3ADF9818>