Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.debian.user > #170799

Re: Problem with NON-STANDARD install

Show all headers | View raw

Le 06/08/2016 à 16:18, Felix Miata a écrit :
> Pascal Hambourg composed on 2016-08-06 12:01 (UTC+0200):
>
(location of GRUB's core image)
>> - or as a regular file in a filesystem appearing as
>> /boot/grub/i386-pc/core.img (or /boot/grub/core.img with older versions
>> of GRUB such as the one in Wheezy). This option is not recommended as
>> the filesystem may move the blocks around and the location of the core
>> image is hardcoded into the boot image.
>
> This "not recommended" philosophy corresponds almost perfectly with the
> practice universally complained about that Windows' installer replaces
> Grub code that it finds in the MBR with its own legacy/generic boot
> code, code which is just as capable of loading Grub code from a primary
> partition's PBR as it is loading Windows code from a primary partition's
> PBR, which is how Windows normally boots. When Grub is installed to a
> primary partition's PBR in the first place, Windows "hijacking" the MBR
> is a non-issue.[1]

I'm not sure I get your point and how it relates to the above.

> As a practical matter, moving core image blocks around is uncommon, and

Indeed, but it may become less uncommon with modern filesystems such as 
ext4 and btrfs. Of course you can stick to good old ext2 for /boot if 
you can afford a separate partition for it.

I also thought about setting the "i" flag (immutable file) with chattr, 
but the manpage does not mention that it prevents the filesystem handler 
from moving the file blocks around for garbage collection, 
defragmentation or whatever.

I once had a boot failure on a system with the core image in /boot/grub. 
The only explaination which came into my mind was that the core image 
blocks had been moved around. FWIW, the filesystem was ext4.

However it might be worth noting that writing GRUB's core image as a 
regular file is perfectly safe if it is not the primary bootloader but 
is chainloaded by another instance of GRUB with the "multiboot" command 
(taking the core image location as argument) instead of the usual 
"chainloader" command (taking the boot sector location as argument).

> just as easily fixed if and when it does occur as is reinstalling Grub
> to the MBR.

Easily fixed only if you can get your hands on the machine and boot a 
rescue system, e.g. by physical/KVM access or network boot.

Back to linux.debian.user | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

Problem with NON-STANDARD install Richard Owlett <rowlett@cloud85.net> - 2016-08-01 17:40 +0200
  Re: Problem with NON-STANDARD install David Wright <deblis@lionunicorn.co.uk> - 2016-08-01 19:10 +0200
    Re: Problem with NON-STANDARD install Richard Owlett <rowlett@cloud85.net> - 2016-08-01 20:10 +0200
      Re: Problem with NON-STANDARD install David Wright <deblis@lionunicorn.co.uk> - 2016-08-01 21:00 +0200
      Re: Problem with NON-STANDARD install Joe <joe@jretrading.com> - 2016-08-01 21:20 +0200
        Re: Problem with NON-STANDARD install Richard Owlett <rowlett@cloud85.net> - 2016-08-01 22:30 +0200
        Re: Problem with NON-STANDARD install Felix Miata <mrmazda@earthlink.net> - 2016-08-02 03:10 +0200
        Re: Problem with NON-STANDARD install Pascal Hambourg <pascal@plouf.fr.eu.org> - 2016-08-06 12:10 +0200
        Re: Problem with NON-STANDARD install Pascal Hambourg <pascal@plouf.fr.eu.org> - 2016-08-06 12:10 +0200
          Re: Problem with NON-STANDARD install Richard Owlett <rowlett@cloud85.net> - 2016-08-06 15:10 +0200
          Re: Problem with NON-STANDARD install Felix Miata <mrmazda@earthlink.net> - 2016-08-06 16:20 +0200
            Re: Problem with NON-STANDARD install Pascal Hambourg <pascal@plouf.fr.eu.org> - 2016-08-07 00:00 +0200
              Re: Problem with NON-STANDARD install Felix Miata <mrmazda@earthlink.net> - 2016-08-07 00:20 +0200
            Re: Problem with NON-STANDARD install Pascal Hambourg <pascal@plouf.fr.eu.org> - 2016-08-07 11:50 +0200
  Re: Problem with NON-STANDARD install Brian Flaherty <bxf4@yahoo.com> - 2016-08-01 19:30 +0200
    Re: Problem with NON-STANDARD install Richard Owlett <rowlett@cloud85.net> - 2016-08-01 20:30 +0200
  Re: Problem with NON-STANDARD install Richard Owlett <rowlett@cloud85.net> - 2016-08-05 20:50 +0200
    Re: Problem with NON-STANDARD install David Wright <deblis@lionunicorn.co.uk> - 2016-08-05 22:10 +0200
      Re: Problem with NON-STANDARD install Richard Owlett <rowlett@cloud85.net> - 2016-08-05 23:10 +0200
      [PRIVATE REPLY} Re: Problem with NON-STANDARD install Richard Owlett <rowlett@cloud85.net> - 2016-08-05 23:20 +0200
    Re: Problem with NON-STANDARD install Richard Owlett <rowlett@cloud85.net> - 2016-09-02 15:40 +0200
      Re: Problem with NON-STANDARD install Felix Miata <mrmazda@earthlink.net> - 2016-09-03 06:30 +0200
        Re: Problem with NON-STANDARD install Lisi Reisz <lisi.reisz@gmail.com> - 2016-09-03 12:40 +0200
          Re: Problem with NON-STANDARD install Gene Heskett <gheskett@shentel.net> - 2016-09-03 13:00 +0200

csiph-web