Re: install-mbr on amd64?
On Sat, May 20, 2006 at 02:07:54AM +0200, Goswin von Brederlow wrote:
> > On Fri, May 19, 2006 at 04:29:36PM +0200, Goswin von Brederlow wrote:
> >> You have to trick grub-install. Say /boot is on /dev/md0, a raid1 of
> >> /dev/sda1 and /dev/sdb1. Then you can put /dev/sda1 into devices.map,
> >> instal-grub, repeat for sdb1. You might have to change fstab and/or
> >> mtab as well. Can't remeber if that is truely needed.
> >>
> ...
> Then pull a disk (the right one) and see it stop booting. From
> grub-install:
> ...
> Only one of your disks is bootable. By setting up each device in
> device.map in turn you get grub on each of them.
>
> MfG
> Goswin
>
Hello,
Goswin is right. I have installed etch on amd64 and configured
RAID1, LVM and grub in d-i.
# BEGIN-CLI
deb64a:~# df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/md1 1829101 189101 1542410 11% /
/dev/md0 60093 19372 37515 35% /boot
...
# END-CLI
After the installation only the MBR on /dev/sda contains meaningful
data, whereas the MBR on /dev/sdb contains mostly zeros.
# BEGIN-CLI
deb64a:~# dd if=/dev/sda bs=512 count=1 | od -v | head -n 12
1+0 records in
1+0 records out
512 bytes (512 B) copied, 2.2e-05 seconds, 23.3 MB/s
0000000 044353 150220 000274 175574 003520 017520 137374 076033
0000020 015677 050006 134527 000745 122363 136713 003676 002261
0000040 067070 076000 072411 101423 010305 172342 014315 172613
0000060 143203 044420 014564 026070 173164 132640 132007 001003
0000100 000377 020000 000001 000000 001000 100372 100312 051752
0000120 000174 030400 107300 107330 136320 020000 120373 076100
0000140 177474 001164 141210 137122 076571 032350 173001 100302
0000160 052164 040664 125273 146525 055023 071122 100511 052773
0000200 072652 120103 076101 140204 002565 160603 072001 063067
0000220 046213 137020 076005 042306 000777 105546 042036 143574
0000240 010004 143400 001104 000001 104546 004134 042307 000006
0000260 063160 140061 042211 063004 042211 132014 146502 071023
deb64a:~# dd if=/dev/sdb bs=512 count=1 | od -v | head -n 12
1+0 records in
1+0 records out
512 bytes (512 B) copied, 2.1e-05 seconds, 24.4 MB/s
0000000 134372 010000 150216 000274 134260 000000 154216 140216
0000020 137373 076000 000277 134406 001000 122363 020752 000006
0000040 137000 003676 002070 005565 143203 100420 177376 072407
0000060 165763 132026 130002 135401 076000 100262 072212 105401
0000100 001114 011715 000352 000174 165400 000376 000000 000000
0000120 000000 000000 000000 000000 000000 000000 000000 000000
0000140 000000 000000 000000 000000 000000 000000 000000 000000
0000160 000000 000000 000000 000000 000000 000000 000000 000000
0000200 000000 000000 000000 000000 000000 000000 000000 000000
0000220 000000 000000 000000 000000 000000 000000 000000 000000
0000240 000000 000000 000000 000000 000000 000000 000000 000000
0000260 000000 000000 000000 000000 000000 000000 000000 000000
# END-CLI
After running 'grub-install' on /dev/sdb, both MBRs, on /dev/sda
and /dev/sdb, contain the right data.
# BEGIN-CLI
deb64a:~# grub-install --root-directory=/boot --no-floppy /dev/sdb
Probing devices to guess BIOS drives. This may take a long time.
Installation finished. No error reported.
This is the contents of the device map /boot/boot/grub/device.map.
Check if this is correct or not. If any of the lines is incorrect,
fix it and re-run the script `grub-install'.
(hd0) /dev/sda
(hd1) /dev/sdb
deb64a:~# dd if=/dev/sda bs=512 count=1 | od -v | head -n 12
1+0 records in
1+0 records out
512 bytes (512 B) copied, 0.000638 seconds, 803 kB/s
0000000 044353 150220 000274 175574 003520 017520 137374 076033
0000020 015677 050006 134527 000745 122363 136713 003676 002261
0000040 067070 076000 072411 101423 010305 172342 014315 172613
0000060 143203 044420 014564 026070 173164 132640 132007 001003
0000100 000377 020000 000001 000000 001000 100372 100312 051752
0000120 000174 030400 107300 107330 136320 020000 120373 076100
0000140 177474 001164 141210 137122 076571 032350 173001 100302
0000160 052164 040664 125273 146525 055023 071122 100511 052773
0000200 072652 120103 076101 140204 002565 160603 072001 063067
0000220 046213 137020 076005 042306 000777 105546 042036 143574
0000240 010004 143400 001104 000001 104546 004134 042307 000006
0000260 063160 140061 042211 063004 042211 132014 146502 071023
deb64a:~# dd if=/dev/sdb bs=512 count=1 | od -v | head -n 12
1+0 records in
1+0 records out
512 bytes (512 B) copied, 0.013082 seconds, 39.1 kB/s
0000000 044353 010220 150216 000274 134260 000000 154216 140216
0000020 137373 076000 000277 134406 001000 122363 020752 000006
0000040 137000 003676 002070 005565 143203 100420 177376 072407
0000060 165763 132026 130002 135401 076000 100262 072212 001003
0000100 000201 020000 000001 000000 001000 110372 173220 100302
0000120 001165 100262 054752 000174 030400 107300 107330 136320
0000140 020000 120373 076100 177474 001164 141210 137122 076577
0000160 032350 173001 100302 052164 040664 125273 146525 055023
0000200 071122 100511 052773 072652 120103 076101 140204 002565
0000220 160603 072001 063067 046213 137020 076005 042306 000777
0000240 105546 042036 143574 010004 143400 001104 000001 104546
0000260 004134 042307 000006 063160 140061 042211 063004 042211
# END-CLI
I did not unplug or replugged the HDs, but I changed the
HD boot order in the BIOS, from IDE-channel2, -channel3 to
IDE-channel3, -channel2, and can boot in both cases.
I think this prooves that grub does not work out of the box
with RAID1 as many might expect, but that it is quite easy
to enable booting from both HDs.
Even if the MBR is missing on the 2nd drive and the
1st drive crashes, one can still install the MBR on the
2nd drive with a rescue CD.
Alexander
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