Re: raid1 bootable disks

[Francesco Pietra <frapietra@alice.it>]

On Thursday 03 August 2006 17:27, Lennart Sorensen wrote:
> On Thu, Aug 03, 2006 at 02:49:11PM +0200, Francesco Pietra wrote:
> > Just to add that
> > #fdisk /dev/sda
> > or
> > #fdisk /dev/sdb
> >
> > followed by
> > p
> >
> > gives the identical layout of partitions for both sda and sdb, in
> > particular
> >
> > Device: /dev/sda1 (or sdb1)
> > Boot: *
> > Start: 1
> > End: 365
> > Blocks: 2931831
> > Id:  fd
> > System: Linux raid autodetect
> >
> > Does that * for boot on both sda and sdb mean anything?
>
> If you have grub installed in the MBR, then it doesn't matter what the
> boot flag is set to on any partition since nothing will look at it.  

>>Except some bios does.

>>MfG
        >>Goswin

Grub went installed on /boot while creating raid1 linux software, at the end 
of installations on the other partitions. Therefore, I understand that I have 
grub installed in the MBR and, importantly, that I have done  all that was 
allowed toward security. Which, in my case is more for the system than the 
data, as I backup the data regularly on two independent external hard disks. 
Also, there is no problem if mpqc calculations are interrupted; actually the 
calculation may take a better path if restarted from the last minimum 
geometry.

Thanks a lot
francesco

> If 
> grub is installed to one of the partitions, then whatever code is in the
> MBR probably does care what partition is bootable, since it has to jump
> to the boot block of that partition.  Of course in that case you do want
> the boot partition set bootable on both drives so that whichever one you
> are booting from, can find the right partition to jump to.  Putting grub
> in the MBR and not worrying at all about the boot flag is the simplest
> however.
>
> --
> Len Sorensen