Syslinux - Aug 2002 - 2 root disks sdb1,sdc1; if set "root=/dev/sdc1", mtab lies saying sdb1 is root!?

I have 2 SCSI disks each w/a RH 7.3 ext3 root filesystem: /dev/sdb1, and
/dev/sdc1.
/dev/sda1 is an old RH4.2 root filesystem. (sdb1 was created as an image of sdc1
using dd.)

I have no problem booting from a SYSLINUX 1.52 floppy with SYSLINUX.CFG
containing "append initrd=initrd.img  root=/dev/sdb1".

When I alter SYSLINUX.CFG with:
"append initrd=initrd.img  root=/dev/sdc1".  The boot also works just
fine:

  dmesg|grep Kernel results in:

    Kernel command line: initrd=initrd.img root=/dev/sdc1 BOOT_IMAGE=vmlinuz -b

THE PROBLEM: the mount command and /etc/mtab indicate
that "/dev/sdb1" is root- I know this is false because the
sdb disk is never accessed (LED never lites) , and because I have
distinct files on sdc not on sdb.  If I reverse the SCSI ids on the 2 RH 7.3
disks the behavior is identical when I boot from /dev/sdc1.

What can be done to clear this up?

Please help or let me know a more appropriate place to post this.


thanks/regards;
--
Tom Rodman
perl -e 'print unpack("u",
"\.\=\$\!T\<F\]D\;6\%N\+F\-O\;0H\`");' #my e-mail address

Tom Rodman wrote:
> 
> THE PROBLEM: the mount command and /etc/mtab indicate
> that "/dev/sdb1" is root- I know this is false because the
> sdb disk is never accessed (LED never lites) , and because I have
> distinct files on sdc not on sdb.  If I reverse the SCSI ids on the 2 RH
7.3
> disks the behavior is identical when I boot from /dev/sdc1.
> 
> What can be done to clear this up?
> 
Fix your /etc/fstab.

	-hpa

Thanks! That did it.

I read the man page on fstab, and then used tune2fs to make a unique
label for the sdc1 partition and used the label in fstab and it seems to work.

Just curious..:
  During boot what happens, I see a chicken egg dilemna - how is fstab read
  without the root partition first getting mounted?  I need a better overview of
the
  boot process.  Is a temporary mount point (not "/") used to read the
partition,
  and later pivot_root used.. I should be looking at source code, right?
  How about another nudge in the right direction; I won't post any more on
  this thread.


-- 
thanks again/regards,
Tom Rodman
perl -e 'print unpack("u",
"\.\=\$\!T\<F\]D\;6\%N\+F\-O\;0H\`");' #my e-mail address
   

On Sun 8/25/02 14:12 CDT Tom Rodman wrote:
>I have 2 SCSI disks each w/a RH 7.3 ext3 root filesystem: /dev/sdb1, and
/dev/sdc1.
>/dev/sda1 is an old RH4.2 root filesystem. (sdb1 was created as an image of
sdc1
>using dd.)
>
>I have no problem booting from a SYSLINUX 1.52 floppy with SYSLINUX.CFG
>containing "append initrd=initrd.img  root=/dev/sdb1".
>
>When I alter SYSLINUX.CFG with:
>"append initrd=initrd.img  root=/dev/sdc1".  The boot also works
just fine:
>
>  dmesg|grep Kernel results in:
>
>    Kernel command line: initrd=initrd.img root=/dev/sdc1 BOOT_IMAGE=vmlinuz
-b
>
>THE PROBLEM: the mount command and /etc/mtab indicate
>that "/dev/sdb1" is root- I know this is false because the
>sdb disk is never accessed (LED never lites) , and because I have
>distinct files on sdc not on sdb.  If I reverse the SCSI ids on the 2 RH 7.3
>disks the behavior is identical when I boot from /dev/sdc1.
>
>What can be done to clear this up?
>
>Please help or let me know a more appropriate place to post this.
>
>
>thanks/regards;
>--
>Tom Rodman
>perl -e 'print unpack("u",
"\.\=\$\!T\<F\]D\;6\%N\+F\-O\;0H\`");' #my e-mail address