On Thu, 06 Nov 2014, Ron Leach wrote: > /dev/sdb is partitioned: > sdb1: /boot2 (this was a simple copy of /boot on /dev/sda1; sda1 and sdb1 > were not raid) > sdb2: (raid1) / > sdb3: (raid1) /usr > sdb4: (raid1) /var > sdb5: swap > sdb6: (raid1) /tmp > sdb7: (raid1) /home > sdb8: (raid1) /userdata > > Could I ask 3 questions? Is there a way I can check whether there is a > correct MBR on /dev/sdb? > > Secondly, /boot on /dev/sda1 had been flagged as bootable, so to boot from > /dev/sdb1 should I now flag /dev/sdb1 as bootable and, if so, how should I > do that from the rescue mode? > > Lastly, do I need to run a grub installer and, if so, where ought I be able > to find that? I tried running grub-install from both a shell in the root > filesystem, and from a shell in the rescue system, but grub-install seemed > not to be there. Perhaps the shell needs a 'path' to find it or, even, some > other partitions mounted.
1) Boot off of rescue media (the Debian installer will work fine) 2) Start the raid for / in degraded mode from the rescue media shell 3) Mount the raid for / on /target or similar 4) Bind mount /dev, and mount /proc and /sys on /target/ as appropriate 5) Chroot into /target; start the other raid devices if necessary, and mount them. You'll at least need /usr. 6) Copy the partition table from /dev/sdb to /dev/sda 7) Add the new partitions from /dev/sda to the raid devices which you have started 8) At this point, I would suggest imaging /dev/sdb1, and turning /dev/sdb1 into a real raid device, and using that as /boot and mounting it on /boot. Copy the files back by mounting the old /dev/sdb1 on a loopback device, not by dd'ing (or similar) /dev/sdb1 to the new raid device. 9) If necessary, bring networking up, and install/reinstall grub. 10) Run grub-install on /dev/sda and /dev/sdb 11) Make sure that /boot now has the correct kernel. (You'll probably want to re-install it anyway, because it's highly likely that you haven't kept /boot2 in sync.) 12) unmount things, exit the chroot, and unmount more. 13) Reboot. You should *at least* get a grub prompt. -- Don Armstrong http://www.donarmstrong.com We cast this message into the cosmos. [...] We are trying to survive our time so we may live into yours. We hope some day, having solved the problems we face, to join a community of Galactic Civilizations. This record represents our hope and our determination and our goodwill in a vast and awesome universe. -- Jimmy Carter on the Voyager Golden Record -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: https://lists.debian.org/20141106163011.gk29...@teltox.donarmstrong.com
