now that i've screwed up and apparently get to start over ...

now that i've screwed up and apparently get to start over ...

[David T-G]

Hi, all --

I have an existing system with a raw-partitioned /dev/sda (128G SSD)
that I plan to convert to a mirrored boot drive.  I installed /dev/sde
(256G SSD) and sliced it the same way (well, with a bigger 4th slice)
and set up half mirrors in each partition.  I've been waiting for the
opportunity to copy the sda partitions over to the new sde mirrors and
then swap sda for a new 256G SSD and add the other half of each mirror.

So now I have just bought another 10T drive to add into the RAID-5 array
(that's a whole separate project, of course), so I shut it all down and
not only plugged in the big drive (but did nothing else with it) but also
copied over each slice and figured hey, yippee, I'll reboot from the mirror
and be another step forward.

Then GRUB puked all over itself and I can't get the stupid thing running
at all now.  I've disconnected /dev/sde, I've disconnected all USB
external drives, I've disconnected all internal drives, I've swapped out
/dev/sda and put /dev/sde back, and I get that GRUB can't boot from a GPT
disk ... except that /dev/sda has always been that!

So now I might as well go ahead and install a fresh version into the
alt-root slice in order to get GRUB working again and then figure out
how to get back to the real-root original.  But ... do I slice the
disk and create four mirrors or do I mirror the disk and create four
partitions therein?  I was happy with four mirrors, but then there's
the question of whether or not GRUB will work, and I don't really want
to have to create another I've-lost-count partitions for /boot and /efi
and whatever.  I've seen so much advice both ways, much of it from 2011
and 2012, that I don't know which way to go!

My goal is to mirror two SSDs and have four

  swap
  real-root
  alt-root
  data

partitions; however I get there so that I can boot from either root works
for me.  Anyone have the "Simple Setup for Dummy David" instruction set?


Thanks in advance!

:-D
-- 
David T-G
See http://justpickone.org/davidtg/email/
See http://justpickone.org/davidtg/tofu.txt

Re: now that i've screwed up and apparently get to start over ...

[Phillip Susi]

David T-G <davidtg-robot@justpickone.org> writes:

> Then GRUB puked all over itself and I can't get the stupid thing running
> at all now.  I've disconnected /dev/sde, I've disconnected all USB
> external drives, I've disconnected all internal drives, I've swapped out
> /dev/sda and put /dev/sde back, and I get that GRUB can't boot from a GPT
> disk ... except that /dev/sda has always been that!

GRUB can boot from GPT just fine.  Assuming you are booting in EFI mode,
it just has to have an EFI system partition, and be registered with the
EFI firmware.  You can't just copy the partitions to a new drive and
remove the old drive and expect it to boot.  You will need to
grub-install on the new drive to register it with the EFI firmware.

Re: now that i've screwed up and apparently get to start over ...

[David T-G]

Phillip, et al --

...and then Phillip Susi said...
% 
% David T-G <davidtg-robot@justpickone.org> writes:
% 
% > Then GRUB puked all over itself and I can't get the stupid thing running
...
% > /dev/sda and put /dev/sde back, and I get that GRUB can't boot from a GPT
% > disk ... except that /dev/sda has always been that!
% 
% GRUB can boot from GPT just fine.  Assuming you are booting in EFI mode,
% it just has to have an EFI system partition, and be registered with the

Ah, but I'm not.  I only have four partitions

  jpo:~ # parted /dev/sda unit MiB p free
  Model: ATA SAMSUNG MZ7LN128 (scsi)
  Disk /dev/sda: 122104MiB
  Sector size (logical/physical): 512B/512B
  Partition Table: gpt
  Disk Flags: pmbr_boot
  
  Number  Start     End        Size      File system     Name      Flags
	  0.02MiB   1.00MiB    0.98MiB   Free Space
   1      1.00MiB   33793MiB   33792MiB  linux-swap(v1)  jpo-swap  swap
   2      33793MiB  66561MiB   32768MiB  xfs             jposuse
   3      66561MiB  99329MiB   32768MiB  xfs             jpoalt    legacy_boot
   4      99329MiB  122104MiB  22775MiB  xfs             jpo-ssd

(taken from an identical machine) and do not use that UEFI stuff that I
don't know.  Way simple.


% EFI firmware.  You can't just copy the partitions to a new drive and
% remove the old drive and expect it to boot.  You will need to
% grub-install on the new drive to register it with the EFI firmware.

Heck, I'd be happy to be booting from the old drive!


Thanks again & HANW

:-D
-- 
David T-G
See http://justpickone.org/davidtg/email/
See http://justpickone.org/davidtg/tofu.txt