Re: install-mbr on amd64?
Alexander Sieck <alexander.sieck@web.de> writes:
> That is, also after changing sda to sdb in device.map, the
> two MBRs are not identical.
>
> Maybe Goswin, or somebody else who enabled booting from both
> disks with RAID1 and grub, can give the output of
> 'dd if=xxx[ab] bs=512 count=1 | od' on their system.
I just dded the mbr from sda to all raid devices making them identical
the last time I installed.
>> > 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.
>>
>> Is that the same as removing a disk or does that preserve sda as hd0
>> and sdb as hd1 and just boot from hd1?
>>
> I also think, that unplugging the 1st disk, is the only hard test
> (and even that may not be sufficient to simulate a real crash).
If a disk fails the system should keep running. Thats the point of
raid after all. So when you do reboot it will usualy be to replace the
disk. So I'm not much concerned if the system is still bootable with a
broken disk still connected. It is likely the bios won't like that at
all no matter what the MBR looks like.
> Since the time I installed my system a couple of months ago, I would
> like to test, how much work it will be to recover from a disk-crash.
> So I am willing to test it the hard way by unplugging the 1st
> disk. But this might take some time. Before doing that, I will
> do a backup and figure out how to synchronize the RAID afterwards.
Install qemu, install a base system with raid1 inside it, start qemu
with just harddisk file.
> This sub-thread fits better to debian-user or debian-boot, since it is
> absolutely not related to amd64. Maybe there the chance is higher
> to get people involved which already tested booting from the 2nd disk.
> Maybe Goswin can report, if he unplugged it.
Haven't rebooted once after installation yet.
> I will inform you after the unplug test, if I do not shoot in my own
> toe and mess up my system:-). It is my private machine and not a
> production server, therefore it is not really critical, but I do
> not want to spent too much time.
>
> Alexander
MfG
Goswin
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